MM-15844: migrate post permanentdeletebyuser to sync by default #10984 (#11056)

app/user.go

@@ -1463,8 +1463,8 @@ func (a *App) PermanentDeleteUser(user *model.User) *model.AppError {
 		return result.Err
 	}
 
-	if result := <-a.Srv.Store.Post().PermanentDeleteByUser(user.Id); result.Err != nil {
-		return result.Err
+	if err := a.Srv.Store.Post().PermanentDeleteByUser(user.Id); err != nil {
+		return err
 	}
 
 	infos, err := a.Srv.Store.FileInfo().GetForUser(user.Id)