Store enum type in settings directly

Affected settings will be migrated to new keys so nothing should break.

PR #15800.

src/webui/api/synccontroller.cpp

@@ -282,7 +282,8 @@ namespace
                     }
                     break;
                 default:
-                    Q_ASSERT(0);
+                    Q_ASSERT(false);
+                    break;
                 }
             }