Replace db count query in user signup process (#18072)

store/retrylayer/retrylayer.go

@@ -11236,6 +11236,26 @@ func (s *RetryLayerUserStore) InvalidateProfilesInChannelCacheByUser(userID stri
 
 }
 
+func (s *RetryLayerUserStore) IsEmpty() (bool, error) {
+
+	tries := 0
+	for {
+		result, err := s.UserStore.IsEmpty()
+		if err == nil {
+			return result, nil
+		}
+		if !isRepeatableError(err) {
+			return result, err
+		}
+		tries++
+		if tries >= 3 {
+			err = errors.Wrap(err, "giving up after 3 consecutive repeatable transaction failures")
+			return result, err
+		}
+	}
+
+}
+
 func (s *RetryLayerUserStore) PermanentDelete(userID string) error {
 
 	tries := 0