Revert "Update check to match client"

This reverts commit f195c1c.

src/Core/OrganizationFeatures/OrganizationSubscriptions/AddSecretsManagerSubscriptionCommand.cs

@@ -91,7 +91,7 @@ private async Task ValidateOrganization(Organization organization)
         }
 
         var provider = await _providerRepository.GetByOrganizationIdAsync(organization.Id);
-        if (provider != null)
+        if (provider is { Type: ProviderType.Msp })
         {
             throw new BadRequestException(
                 "Organizations with a Managed Service Provider do not support Secrets Manager.");