[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

src/Api/Auth/Validators/EmergencyAccessRotationValidator.cs

@@ -24,13 +24,9 @@ public class EmergencyAccessRotationValidator : IRotationValidator<IEnumerable<E
         IEnumerable<EmergencyAccessWithIdRequestModel> emergencyAccessKeys)
     {
         var result = new List<EmergencyAccess>();
-        if (emergencyAccessKeys == null || !emergencyAccessKeys.Any())
-        {
-            return result;
-        }
 
         var existing = await _emergencyAccessRepository.GetManyDetailsByGrantorIdAsync(user.Id);
-        if (existing == null || !existing.Any())
+        if (existing == null || existing.Count == 0)
         {
             return result;
         }