refactor(ui): Remove SafeArea where they are not needed

lib/ui/pages/onboarding/onboarding.dart

@@ -21,8 +21,7 @@ class _OnboardingPageState extends State<OnboardingPage> {
   }
 
   @override
-  Widget build(final BuildContext context) => SafeArea(
+  Widget build(final BuildContext context) => Scaffold(
-        child: Scaffold(
     body: PageView(
       controller: pageController,
       children: [
@@ -30,7 +29,6 @@ class _OnboardingPageState extends State<OnboardingPage> {
         _withPadding(secondPage()),
       ],
     ),
-        ),
   );
 
   Widget _withPadding(final Widget child) => Padding(
@@ -60,8 +58,7 @@ class _OnboardingPageState extends State<OnboardingPage> {
                     style: Theme.of(context).textTheme.bodyMedium,
                   ),
                   const SizedBox(height: 32),
-                  Flexible(
+                  Center(
-                    child: Center(
                     child: Image.asset(
                       _fileName(
                         context: context,
@@ -71,7 +68,6 @@ class _OnboardingPageState extends State<OnboardingPage> {
                       ),
                     ),
                   ),
-                  ),
                 ],
               ),
             ),

lib/ui/pages/root_route.dart

@@ -52,8 +52,7 @@ class _RootPageState extends State<RootPage> with TickerProviderStateMixin {
     final bool isReady = context.watch<ServerInstallationCubit>().state
         is ServerInstallationFinished;
 
-    return SafeArea(
+    return Provider<ChangeTab>(
-      child: Provider<ChangeTab>(
       create: (final _) => ChangeTab(tabController.animateTo),
       child: Scaffold(
         body: TabBarView(
@@ -86,7 +85,6 @@ class _RootPageState extends State<RootPage> with TickerProviderStateMixin {
               )
             : null,
       ),
-      ),
     );
   }
 }