revert: WillPopScope migration

This reverts commit ef9b1d5c2d.

Why is this so hard to implement??? Are we missing something??

lib/services/manager_api.dart

@@ -619,8 +619,8 @@ class ManagerAPI {
     return showDialog(
       barrierDismissible: false,
       context: context,
-      builder: (context) => PopScope(
-        canPop: false,
+      builder: (context) => WillPopScope(
+        onWillPop: () async => false,
         child: AlertDialog(
           title: Text(t.warning),
           content: ValueListenableBuilder(

lib/ui/views/installer/installer_view.dart

@@ -16,9 +16,12 @@ class InstallerView extends StatelessWidget {
     return ViewModelBuilder<InstallerViewModel>.reactive(
       onViewModelReady: (model) => model.initialize(context),
       viewModelBuilder: () => InstallerViewModel(),
-      builder: (context, model, child) => PopScope(
-        onPopInvoked: (bool didPop) => model.onWillPop(context),
-        canPop: false,
+      builder: (context, model, child) => WillPopScope(
+        /* 
+          TODO(any): migrate to [PopScope],
+          we've tried to migrate it two times but 
+          reverted it because we couldn't exit out of the screen. 
+        */
         child: SafeArea(
           top: false,
           bottom: model.isPatching,
@@ -108,6 +111,7 @@ class InstallerView extends StatelessWidget {
             ),
           ),
         ),
+        onWillPop: () => model.onWillPop(context),
       ),
     );
   }

lib/ui/views/navigation/navigation_view.dart

@@ -13,10 +13,14 @@ class NavigationView extends StatelessWidget {
     return ViewModelBuilder<NavigationViewModel>.reactive(
       onViewModelReady: (model) => model.initialize(context),
       viewModelBuilder: () => locator<NavigationViewModel>(),
-      builder: (context, model, child) => PopScope(
-        canPop: model.currentIndex == 0,
-        onPopInvoked: (bool didPop) => {
-          if (!didPop) model.setIndex(0),
+      builder: (context, model, child) => WillPopScope(
+        onWillPop: () async {
+          if (model.currentIndex == 0) {
+            return true;
+          } else {
+            model.setIndex(0);
+            return false;
+          }
         },
         child: Scaffold(
           body: PageTransitionSwitcher(