refactor(neon,app): Drop unused loginName

packages/app/integration_test/screenshot_test.dart

@@ -129,7 +129,6 @@ Future main() async {
   final binding = IntegrationTestWidgetsFlutterBinding.ensureInitialized();
   final account = Account(
     serverURL: 'http://10.0.2.2',
-    loginName: 'user1',
     username: 'user1',
     password: 'user1',
   );
@@ -346,7 +345,6 @@ Future main() async {
   testWidgets('notifications', (final tester) async {
     await Account(
       serverURL: 'http://10.0.2.2',
-      loginName: 'admin',
       username: 'admin',
       password: 'admin',
     ).client.notifications.sendAdminNotification(

packages/neon/neon/lib/src/blocs/login_check_account.dart

@@ -53,7 +53,6 @@ class LoginCheckAccountBloc extends InteractiveBloc
 
       final account = Account(
         serverURL: serverURL,
-        loginName: loginName,
         username: response.ocs.data.id,
         password: password,
         userAgent: neonUserAgent,

packages/neon/neon/lib/src/models/account.dart

@@ -27,14 +27,12 @@ abstract interface class Credentials {
 class Account implements Credentials {
   Account({
     required this.serverURL,
-    required this.loginName,
     required this.username,
     this.password,
     this.userAgent,
   }) : _client = NextcloudClient(
           serverURL,
-          loginName: loginName,
+          loginName: username,
-          username: username,
           password: password,
           userAgentOverride: userAgent,
           cookieJar: CookieJar(),
@@ -45,7 +43,6 @@ class Account implements Credentials {
 
   @override
   final String serverURL;
-  final String loginName;
   @override
   final String username;
   @override
@@ -56,7 +53,6 @@ class Account implements Credentials {
   bool operator ==(final Object other) =>
       other is Account &&
       other.serverURL == serverURL &&
-      other.loginName == loginName &&
       other.username == username &&
       other.password == password &&
       other.userAgent == userAgent;