Enable credential autofill for signup and login (#56)

frontend/app/test/auth_services_test.dart

@@ -92,6 +92,14 @@ void main() {
           findsOneWidget,
         );
         expect(find.byKey(const ValueKey('verification-sent')), findsNothing);
+        expect(
+          tester.testTextInput.log,
+          isNot(
+            contains(
+              isMethodCall('TextInput.finishAutofillContext', arguments: true),
+            ),
+          ),
+        );
         expect(
           tester
               .widget<TextFormField>(find.byKey(const ValueKey('email')))
@@ -153,6 +161,14 @@ void main() {
       '/verification-sent',
     );
     expect(backend.sends, 1);
+    expect(
+      tester.testTextInput.log,
+      isNot(
+        contains(
+          isMethodCall('TextInput.finishAutofillContext', arguments: true),
+        ),
+      ),
+    );
     expect(
       find.textContaining('a verification email is on its way'),
       findsOneWidget,
@@ -198,6 +214,14 @@ void main() {
         find.text('Сервис недоступен. Попробуйте ещё раз.'),
         findsOneWidget,
       );
+      expect(
+        tester.testTextInput.log,
+        isNot(
+          contains(
+            isMethodCall('TextInput.finishAutofillContext', arguments: true),
+          ),
+        ),
+      );
       await tester.tap(button);
       await tester.pump();
       expect(service.calls, hasLength(2));
@@ -207,6 +231,12 @@ void main() {
       await tester.pumpAndSettle();
       expect(find.byKey(const ValueKey('preview-result')), findsOneWidget);
       expect(find.byKey(const ValueKey('auth-error')), findsNothing);
+      expect(
+        tester.testTextInput.log,
+        contains(
+          isMethodCall('TextInput.finishAutofillContext', arguments: true),
+        ),
+      );
       expect(tester.takeException(), isNull);
     },
   );
@@ -237,6 +267,14 @@ void main() {
     await tester.pumpAndSettle();
     expect(find.byKey(const ValueKey('confirmation')), findsOneWidget);
     expect(find.byKey(const ValueKey('preview-result')), findsNothing);
+    expect(
+      tester.testTextInput.log,
+      isNot(
+        contains(
+          isMethodCall('TextInput.finishAutofillContext', arguments: true),
+        ),
+      ),
+    );
     expect(tester.takeException(), isNull);
   });
 }