fix: improve server connection handling during authentication

- Updated AuthStateManager to clear the active server ID upon logout, ensuring a proper return to the server connection page.
- Enhanced RouterNotifier to allow users to stay on the server connection page if authenticated, improving navigation flow.
- Modified AuthenticationPage to navigate back to the server connection page instead of popping the navigation stack, enhancing user experience during server setup.

lib/features/auth/views/authentication_page.dart

@@ -205,7 +205,7 @@ class _AuthenticationPageState extends ConsumerState<AuthenticationPage> {
       children: [
         ConduitIconButton(
           icon: Platform.isIOS ? CupertinoIcons.back : Icons.arrow_back,
-          onPressed: () => Navigator.pop(context),
+          onPressed: () => context.go(Routes.serverConnection),
           tooltip: AppLocalizations.of(context)!.backToServerSetup,
         ),
         const Spacer(),