[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/AdminConsole/Validators/OrganizationUserRotationValidator.cs

@@ -27,13 +27,9 @@ public class OrganizationUserRotationValidator : IRotationValidator<IEnumerable<
         }
 
         var result = new List<OrganizationUser>();
-        if (resetPasswordKeys == null || !resetPasswordKeys.Any())
-        {
-            return result;
-        }
 
         var existing = await _organizationUserRepository.GetManyByUserAsync(user.Id);
-        if (existing == null || !existing.Any())
+        if (existing == null || existing.Count == 0)
         {
             return result;
         }