[PM-12493] Extract ConfirmUser methods from OrganizationService into commands (#5505)

* Add ConfirmOrganizationUserCommand and IConfirmOrganizationUserCommand interface for managing organization user confirmations

* Add unit tests for ConfirmOrganizationUserCommand to validate user confirmation scenarios

* Register ConfirmOrganizationUserCommand for dependency injection

* Refactor OrganizationUsersController to utilize IConfirmOrganizationUserCommand for user confirmation processes

* Remove ConfirmUserAsync and ConfirmUsersAsync methods from IOrganizationService and OrganizationService

* Rename test methods in ConfirmOrganizationUserCommandTests for clarity and consistency

* Update test method name in ConfirmOrganizationUserCommandTests for improved clarity

src/Core/AdminConsole/OrganizationFeatures/OrganizationUsers/Interfaces/IConfirmOrganizationUserCommand.cs

@@ -0,0 +1,30 @@
+using Bit.Core.Entities;
+
+namespace Bit.Core.AdminConsole.OrganizationFeatures.OrganizationUsers.Interfaces;
+
+/// <summary>
+/// Command to confirm organization users who have accepted their invitations.
+/// </summary>
+public interface IConfirmOrganizationUserCommand
+{
+    /// <summary>
+    /// Confirms a single organization user who has accepted their invitation.
+    /// </summary>
+    /// <param name="organizationId">The ID of the organization.</param>
+    /// <param name="organizationUserId">The ID of the organization user to confirm.</param>
+    /// <param name="key">The encrypted organization key for the user.</param>
+    /// <param name="confirmingUserId">The ID of the user performing the confirmation.</param>
+    /// <returns>The confirmed organization user.</returns>
+    /// <exception cref="BadRequestException">Thrown when the user is not valid or cannot be confirmed.</exception>
+    Task<OrganizationUser> ConfirmUserAsync(Guid organizationId, Guid organizationUserId, string key, Guid confirmingUserId);
+
+    /// <summary>
+    /// Confirms multiple organization users who have accepted their invitations.
+    /// </summary>
+    /// <param name="organizationId">The ID of the organization.</param>
+    /// <param name="keys">A dictionary mapping organization user IDs to their encrypted organization keys.</param>
+    /// <param name="confirmingUserId">The ID of the user performing the confirmation.</param>
+    /// <returns>A list of tuples containing the organization user and an error message (if any).</returns>
+    Task<List<Tuple<OrganizationUser, string>>> ConfirmUsersAsync(Guid organizationId, Dictionary<Guid, string> keys,
+        Guid confirmingUserId);
+}