[MM-61691] Deleting drafts when permanently deleting a user (#30233)

* deleting drafts on permanently deleting user

* verified count of drafts before deleting

* i18n fix

* use ExecBuilder

* changed error message to specify user

---------

Co-authored-by: Mattermost Build <build@mattermost.com>
Co-authored-by: Harshil Sharma <harshilsharma63@gmail.com>

server/channels/store/retrylayer/retrylayer.go

@@ -4209,6 +4209,27 @@ func (s *RetryLayerDraftStore) GetLastCreateAtAndUserIdValuesForEmptyDraftsMigra
 
 }
 
+func (s *RetryLayerDraftStore) PermanentDeleteByUser(userId string) error {
+
+	tries := 0
+	for {
+		err := s.DraftStore.PermanentDeleteByUser(userId)
+		if err == nil {
+			return nil
+		}
+		if !isRepeatableError(err) {
+			return err
+		}
+		tries++
+		if tries >= 3 {
+			err = errors.Wrap(err, "giving up after 3 consecutive repeatable transaction failures")
+			return err
+		}
+		timepkg.Sleep(100 * timepkg.Millisecond)
+	}
+
+}
+
 func (s *RetryLayerDraftStore) Upsert(d *model.Draft) (*model.Draft, error) {
 
 	tries := 0