Reverts "Add generic type for result in PopScope (#139164)" (#147015)

Reverts: flutter/flutter#139164
Initiated by: chunhtai
Reason for reverting: hard breaking change
Original PR Author: chunhtai

Reviewed By: {justinmc}

This change reverts the following previous change:
Adds a generic type and pop result to popscope and its friend.

The use cases are to be able to capture the result when the pop is called.

migration guide: flutter/website#9872

Author: auto-submit[bot]

dev/integration_tests/flutter_gallery/lib/demo/cupertino/cupertino_navigation_demo.dart

@@ -48,7 +48,7 @@ class CupertinoNavigationDemo extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return PopScope<Object?>(
+    return PopScope(
       // Prevent swipe popping of this page. Use explicit exit buttons only.
       canPop: false,
       child: DefaultTextStyle(

dev/integration_tests/flutter_gallery/lib/demo/material/full_screen_dialog_demo.dart

@@ -110,7 +110,7 @@ class FullScreenDialogDemoState extends State<FullScreenDialogDemo> {
   bool _hasName = false;
   late String _eventName;
 
-  Future<void> _handlePopInvoked(bool didPop, Object? result) async {
+  Future<void> _handlePopInvoked(bool didPop) async {
     if (didPop) {
       return;
     }

dev/integration_tests/flutter_gallery/lib/demo/material/text_form_field_demo.dart

@@ -143,7 +143,7 @@ class TextFormFieldDemoState extends State<TextFormFieldDemo> {
     return null;
   }
 
-  Future<void> _handlePopInvoked(bool didPop, Object? result) async {
+  Future<void> _handlePopInvoked(bool didPop) async {
     if (didPop) {
       return;
     }

dev/integration_tests/flutter_gallery/lib/demo/shrine/expanding_bottom_sheet.dart

@@ -355,7 +355,7 @@ class ExpandingBottomSheetState extends State<ExpandingBottomSheet> with TickerP
 
   // Closes the cart if the cart is open, otherwise exits the app (this should
   // only be relevant for Android).
-  void _handlePopInvoked(bool didPop, Object? result) {
+  void _handlePopInvoked(bool didPop) {
     if (didPop) {
       return;
     }
@@ -370,7 +370,7 @@ class ExpandingBottomSheetState extends State<ExpandingBottomSheet> with TickerP
       duration: const Duration(milliseconds: 225),
       curve: Curves.easeInOut,
       alignment: FractionalOffset.topLeft,
-      child: PopScope<Object?>(
+      child: PopScope(
         canPop: !_isOpen,
         onPopInvoked: _handlePopInvoked,
         child: AnimatedBuilder(

dev/integration_tests/flutter_gallery/lib/gallery/home.dart

@@ -326,9 +326,9 @@ class _GalleryHomeState extends State<GalleryHome> with SingleTickerProviderStat
       backgroundColor: isDark ? _kFlutterBlue : theme.primaryColor,
       body: SafeArea(
         bottom: false,
-        child: PopScope<Object?>(
+        child: PopScope(
           canPop: _category == null,
-          onPopInvoked: (bool didPop, Object? result) {
+          onPopInvoked: (bool didPop) {
             if (didPop) {
               return;
             }

examples/api/lib/widgets/form/form.1.dart

@@ -111,7 +111,7 @@ class _SaveableFormState extends State<_SaveableForm> {
           const SizedBox(height: 20.0),
           Form(
             canPop: !_isDirty,
-            onPopInvoked: (bool didPop, Object? result) async {
+            onPopInvoked: (bool didPop) async {
               if (didPop) {
                 return;
               }

examples/api/lib/widgets/pop_scope/pop_scope.0.dart

@@ -109,9 +109,9 @@ class _PageTwoState extends State<_PageTwo> {
           mainAxisAlignment: MainAxisAlignment.center,
           children: <Widget>[
             const Text('Page Two'),
-            PopScope<Object?>(
+            PopScope(
               canPop: false,
-              onPopInvoked: (bool didPop, Object? result) async {
+              onPopInvoked: (bool didPop) async {
                 if (didPop) {
                   return;
                 }

examples/api/lib/widgets/pop_scope/pop_scope.1.dart

@@ -1230,9 +1230,9 @@ class _MasterDetailFlowState extends State<_MasterDetailFlow> implements _PageOp
   }
 
   MaterialPageRoute<void> _detailPageRoute(Object? arguments) {
-    return MaterialPageRoute<void>(builder: (BuildContext context) {
-      return PopScope<void>(
-        onPopInvoked: (bool didPop, void result) {
+    return MaterialPageRoute<dynamic>(builder: (BuildContext context) {
+      return PopScope(
+        onPopInvoked: (bool didPop) {
           // No need for setState() as rebuild happens on navigation pop.
           focus = _Focus.master;
         },