[AC-1910] Allocate seats to a provider organization (#3936)

* Add endpoint to update a provider organization's seats for consolidated billing.

* Fixed failing tests

src/Api/Billing/Controllers/ProviderOrganizationController.cs

@@ -0,0 +1,63 @@
+using Bit.Api.Billing.Models;
+using Bit.Core;
+using Bit.Core.AdminConsole.Repositories;
+using Bit.Core.Billing.Commands;
+using Bit.Core.Context;
+using Bit.Core.Repositories;
+using Bit.Core.Services;
+using Microsoft.AspNetCore.Mvc;
+
+namespace Bit.Api.Billing.Controllers;
+
+[Route("providers/{providerId:guid}/organizations")]
+public class ProviderOrganizationController(
+    IAssignSeatsToClientOrganizationCommand assignSeatsToClientOrganizationCommand,
+    ICurrentContext currentContext,
+    IFeatureService featureService,
+    ILogger<ProviderOrganizationController> logger,
+    IOrganizationRepository organizationRepository,
+    IProviderRepository providerRepository,
+    IProviderOrganizationRepository providerOrganizationRepository) : Controller
+{
+    [HttpPut("{providerOrganizationId:guid}")]
+    public async Task<IResult> UpdateAsync(
+        [FromRoute] Guid providerId,
+        [FromRoute] Guid providerOrganizationId,
+        [FromBody] UpdateProviderOrganizationRequestBody requestBody)
+    {
+        if (!featureService.IsEnabled(FeatureFlagKeys.EnableConsolidatedBilling))
+        {
+            return TypedResults.NotFound();
+        }
+
+        if (!currentContext.ProviderProviderAdmin(providerId))
+        {
+            return TypedResults.Unauthorized();
+        }
+
+        var provider = await providerRepository.GetByIdAsync(providerId);
+
+        var providerOrganization = await providerOrganizationRepository.GetByIdAsync(providerOrganizationId);
+
+        if (provider == null || providerOrganization == null)
+        {
+            return TypedResults.NotFound();
+        }
+
+        var organization = await organizationRepository.GetByIdAsync(providerOrganization.OrganizationId);
+
+        if (organization == null)
+        {
+            logger.LogError("The organization ({OrganizationID}) represented by provider organization ({ProviderOrganizationID}) could not be found.", providerOrganization.OrganizationId, providerOrganization.Id);
+
+            return TypedResults.Problem();
+        }
+
+        await assignSeatsToClientOrganizationCommand.AssignSeatsToClientOrganization(
+            provider,
+            organization,
+            requestBody.AssignedSeats);
+
+        return TypedResults.NoContent();
+    }
+}