gdmUtil: Fix ShellUserVerifier retry logic

Don't call the _retry() function if we are done trying.

Fallout from 8cfd4c969b.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2412>

js/gdm/util.js

@@ -719,10 +719,10 @@ var ShellUserVerifier = class extends Signals.EventEmitter {
                 this._disconnectSignals();
                 await this._handlePendingMessages();
                 this._cancelAndReset();
-            }
-
+            } else {
                 await this._handlePendingMessages();
                 this._retry(serviceName);
+            }
         } catch (e) {
             if (!e.matches(Gio.IOErrorEnum, Gio.IOErrorEnum.CANCELLED))
                 logError(e);