[PM-5938] Prevent permanent vault coruption on key-rotation with desycned vault (#4098)

* Add check to verify the vault state for rotation is not obviously desynced (empty)

* Add unit test for key rotation guardrail

* Move de-synced vault detection to validators

* Add tests

test/Core.Test/Auth/UserFeatures/UserKey/RotateUserKeyCommandTests.cs

@@ -49,4 +49,5 @@ public class RotateUserKeyCommandTests
         await sutProvider.GetDependency<IPushNotificationService>().ReceivedWithAnyArgs()
             .PushLogOutAsync(default, default);
     }
+
 }