[PM-25913] Fix owners unable to rename provider-managed organization (#6599)

And other refactors:
- move update organization method to a command
- separate authorization from business logic
- add tests
- move Billing Team logic into their service

test/Api.IntegrationTest/Helpers/ProviderTestHelpers.cs

@@ -0,0 +1,77 @@
+using Bit.Api.IntegrationTest.Factories;
+using Bit.Core.AdminConsole.Entities.Provider;
+using Bit.Core.AdminConsole.Enums.Provider;
+using Bit.Core.AdminConsole.Repositories;
+using Bit.Core.Repositories;
+
+namespace Bit.Api.IntegrationTest.Helpers;
+
+public static class ProviderTestHelpers
+{
+    /// <summary>
+    /// Creates a provider and links it to an organization.
+    /// This does NOT create any provider users.
+    /// </summary>
+    /// <param name="factory">The API application factory</param>
+    /// <param name="organizationId">The organization ID to link to the provider</param>
+    /// <param name="providerType">The type of provider to create</param>
+    /// <param name="providerStatus">The provider status (defaults to Created)</param>
+    /// <returns>The created provider</returns>
+    public static async Task<Provider> CreateProviderAndLinkToOrganizationAsync(
+        ApiApplicationFactory factory,
+        Guid organizationId,
+        ProviderType providerType,
+        ProviderStatusType providerStatus = ProviderStatusType.Created)
+    {
+        var providerRepository = factory.GetService<IProviderRepository>();
+        var providerOrganizationRepository = factory.GetService<IProviderOrganizationRepository>();
+
+        // Create the provider
+        var provider = await providerRepository.CreateAsync(new Provider
+        {
+            Name = $"Test {providerType} Provider",
+            BusinessName = $"Test {providerType} Provider Business",
+            BillingEmail = $"provider-{providerType.ToString().ToLower()}@example.com",
+            Type = providerType,
+            Status = providerStatus,
+            Enabled = true
+        });
+
+        // Link the provider to the organization
+        await providerOrganizationRepository.CreateAsync(new ProviderOrganization
+        {
+            ProviderId = provider.Id,
+            OrganizationId = organizationId,
+            Key = "test-provider-key"
+        });
+
+        return provider;
+    }
+
+    /// <summary>
+    /// Creates a providerUser for a provider.
+    /// </summary>
+    public static async Task<ProviderUser> CreateProviderUserAsync(
+        ApiApplicationFactory factory,
+        Guid providerId,
+        string userEmail,
+        ProviderUserType providerUserType)
+    {
+        var userRepository = factory.GetService<IUserRepository>();
+        var user = await userRepository.GetByEmailAsync(userEmail);
+        if (user is null)
+        {
+            throw new Exception("No user found in test setup.");
+        }
+
+        var providerUserRepository = factory.GetService<IProviderUserRepository>();
+        return await providerUserRepository.CreateAsync(new ProviderUser
+        {
+            ProviderId = providerId,
+            Status = ProviderUserStatusType.Confirmed,
+            UserId = user.Id,
+            Key = Guid.NewGuid().ToString(),
+            Type = providerUserType
+        });
+    }
+}