[PM-21031] Optimize GET Members endpoint performance (#5907)

* Add new feature flag for Members Get Endpoint Optimization

* Add a new version of OrganizationUser_ReadByOrganizationIdWithClaimedDomains that uses CTE for better performance

* Add stored procedure OrganizationUserUserDetails_ReadByOrganizationId_V2 for retrieving user details, group associations, and collection associations by organization ID.

* Add the sql migration script to add the new stored procedures

* Introduce GetManyDetailsByOrganizationAsync_vNext and GetManyByOrganizationWithClaimedDomainsAsync_vNext in IOrganizationUserRepository to enhance performance by reducing database round trips.

* Updated GetOrganizationUsersClaimedStatusQuery to use an optimized query when the feature flag is enabled

* Updated OrganizationUserUserDetailsQuery to use optimized queries when the feature flag is enabled

* Add integration tests for GetManyDetailsByOrganizationAsync_vNext

* Add integration tests for GetManyByOrganizationWithClaimedDomainsAsync_vNext to validate behavior with verified and unverified domains.

* Optimize performance by conditionally setting permissions only for Custom user types in OrganizationUserUserDetailsQuery.

* Create UserEmailDomainView to extract email domains from users' email addresses

* Create stored procedure Organization_ReadByClaimedUserEmailDomain_V2 that uses UserEmailDomainView to fetch Email domains

* Add GetByVerifiedUserEmailDomainAsync_vNext method to IOrganizationRepository and its implementations

* Refactor OrganizationUser_ReadByOrganizationIdWithClaimedDomains_V2 stored procedure to use UserEmailDomainView for email domain extraction, improving query efficiency and clarity.

* Enhance IOrganizationUserRepository with detailed documentation for GetManyDetailsByOrganizationAsync method, clarifying its purpose and performance optimizations. Added remarks for better understanding of its functionality.

* Fix missing newline at the end of Organization_ReadByClaimedUserEmailDomain_V2.sql to adhere to coding standards.

* Update the database migration script to include UserEmailDomainView

* Bumped the date on the migration script

* Remove GetByVerifiedUserEmailDomainAsync_vNext method and its stored procedure.

* Refactor UserEmailDomainView index creation to check for existence before creation

* Update OrganizationUser_ReadByOrganizationIdWithClaimedDomains_V2 to use CTE and add indexes

* Remove creation of unique clustered index from UserEmailDomainView and related migration script adjustments

* Update indexes and sproc

* Fix index name when checking if it already exists

* Bump up date on migration script

src/Infrastructure.Dapper/AdminConsole/Repositories/OrganizationUserRepository.cs

@@ -268,6 +268,68 @@ public class OrganizationUserRepository : Repository<OrganizationUser, Guid>, IO
         }
     }
 
+    public async Task<ICollection<OrganizationUserUserDetails>> GetManyDetailsByOrganizationAsync_vNext(Guid organizationId, bool includeGroups, bool includeCollections)
+    {
+        using (var connection = new SqlConnection(ConnectionString))
+        {
+            // Use a single call that returns multiple result sets
+            var results = await connection.QueryMultipleAsync(
+                "[dbo].[OrganizationUserUserDetails_ReadByOrganizationId_V2]",
+                new
+                {
+                    OrganizationId = organizationId,
+                    IncludeGroups = includeGroups,
+                    IncludeCollections = includeCollections
+                },
+                commandType: CommandType.StoredProcedure);
+
+            // Read the user details (first result set)
+            var users = (await results.ReadAsync<OrganizationUserUserDetails>()).ToList();
+
+            // Read group associations (second result set, if requested)
+            Dictionary<Guid, List<Guid>>? userGroupMap = null;
+            if (includeGroups)
+            {
+                var groupUsers = await results.ReadAsync<GroupUser>();
+                userGroupMap = groupUsers
+                    .GroupBy(gu => gu.OrganizationUserId)
+                    .ToDictionary(g => g.Key, g => g.Select(gu => gu.GroupId).ToList());
+            }
+
+            // Read collection associations (third result set, if requested)
+            Dictionary<Guid, List<CollectionAccessSelection>>? userCollectionMap = null;
+            if (includeCollections)
+            {
+                var collectionUsers = await results.ReadAsync<CollectionUser>();
+                userCollectionMap = collectionUsers
+                    .GroupBy(cu => cu.OrganizationUserId)
+                    .ToDictionary(g => g.Key, g => g.Select(cu => new CollectionAccessSelection
+                    {
+                        Id = cu.CollectionId,
+                        ReadOnly = cu.ReadOnly,
+                        HidePasswords = cu.HidePasswords,
+                        Manage = cu.Manage
+                    }).ToList());
+            }
+
+            // Map the associations to users
+            foreach (var user in users)
+            {
+                if (userGroupMap != null)
+                {
+                    user.Groups = userGroupMap.GetValueOrDefault(user.Id, new List<Guid>());
+                }
+
+                if (userCollectionMap != null)
+                {
+                    user.Collections = userCollectionMap.GetValueOrDefault(user.Id, new List<CollectionAccessSelection>());
+                }
+            }
+
+            return users;
+        }
+    }
+
     public async Task<ICollection<OrganizationUserOrganizationDetails>> GetManyDetailsByUserAsync(Guid userId,
         OrganizationUserStatusType? status = null)
     {
@@ -558,6 +620,19 @@ public class OrganizationUserRepository : Repository<OrganizationUser, Guid>, IO
         }
     }
 
+    public async Task<ICollection<OrganizationUser>> GetManyByOrganizationWithClaimedDomainsAsync_vNext(Guid organizationId)
+    {
+        using (var connection = new SqlConnection(ConnectionString))
+        {
+            var results = await connection.QueryAsync<OrganizationUser>(
+                $"[{Schema}].[OrganizationUser_ReadByOrganizationIdWithClaimedDomains_V2]",
+                new { OrganizationId = organizationId },
+                commandType: CommandType.StoredProcedure);
+
+            return results.ToList();
+        }
+    }
+
     public async Task RevokeManyByIdAsync(IEnumerable<Guid> organizationUserIds)
     {
         await using var connection = new SqlConnection(ConnectionString);