feat: remove debug banner and make header font color black

lib/android/android_app.dart

@@ -12,6 +12,7 @@ class AndroidApp extends StatelessWidget {
   Widget build(BuildContext context) {
     final box = Hive.box<User>('USER_BOX');
     return MaterialApp(
+      debugShowCheckedModeBanner: false,
       title: 'Flutter Demo',
       theme: ThemeData(
         scaffoldBackgroundColor: Colors.grey.shade200, //<-- SEE

lib/android/pages/welcome.dart

@@ -14,7 +14,12 @@ class _OnboardingPageState extends State<OnboardingPage> {
   Widget build(BuildContext context) {
     return Scaffold(
       appBar: AppBar(
-        title: const Text("Welcome"),
+        title: const Text(
+            "Welcome",
+          style: TextStyle(
+            color: Colors.black
+          ),
+        ),
         backgroundColor: Colors.grey.shade100,
       ),
       body: const FormBuilderComponent(lockTextFields: false,)