[web] Fix page up page down home end shortcut behavior on web…

… (#135454)

We delegate page up / page down actions to the browser. However, we don't let the browser scroll the underlying `<textarea>` - the framework handles scrolling, so page up/down don't end up doing anything. Since the framework handles scrolling for text inputs and textareas, we should let it also handle the actions for `page up`, `page down`, `home`, `end`, and their modifiers. 

fixes flutter/flutter#121867

packages/flutter/lib/src/widgets/default_text_editing_shortcuts.dart

@@ -419,10 +419,6 @@ class DefaultTextEditingShortcuts extends StatelessWidget {
     SingleActivator(LogicalKeyboardKey.arrowLeft, meta: true): DoNothingAndStopPropagationTextIntent(),
     SingleActivator(LogicalKeyboardKey.arrowRight, meta: true): DoNothingAndStopPropagationTextIntent(),
     SingleActivator(LogicalKeyboardKey.arrowUp, meta: true): DoNothingAndStopPropagationTextIntent(),
-    SingleActivator(LogicalKeyboardKey.pageUp, shift: true): DoNothingAndStopPropagationTextIntent(),
-    SingleActivator(LogicalKeyboardKey.pageDown, shift: true): DoNothingAndStopPropagationTextIntent(),
-    SingleActivator(LogicalKeyboardKey.end, shift: true): DoNothingAndStopPropagationTextIntent(),
-    SingleActivator(LogicalKeyboardKey.home, shift: true): DoNothingAndStopPropagationTextIntent(),
     SingleActivator(LogicalKeyboardKey.arrowDown): DoNothingAndStopPropagationTextIntent(),
     SingleActivator(LogicalKeyboardKey.arrowLeft): DoNothingAndStopPropagationTextIntent(),
     SingleActivator(LogicalKeyboardKey.arrowRight): DoNothingAndStopPropagationTextIntent(),
@@ -431,12 +427,6 @@ class DefaultTextEditingShortcuts extends StatelessWidget {
     SingleActivator(LogicalKeyboardKey.arrowRight, control: true): DoNothingAndStopPropagationTextIntent(),
     SingleActivator(LogicalKeyboardKey.arrowLeft, shift: true, control: true): DoNothingAndStopPropagationTextIntent(),
     SingleActivator(LogicalKeyboardKey.arrowRight, shift: true, control: true): DoNothingAndStopPropagationTextIntent(),
-    SingleActivator(LogicalKeyboardKey.pageUp): DoNothingAndStopPropagationTextIntent(),
-    SingleActivator(LogicalKeyboardKey.pageDown): DoNothingAndStopPropagationTextIntent(),
-    SingleActivator(LogicalKeyboardKey.end): DoNothingAndStopPropagationTextIntent(),
-    SingleActivator(LogicalKeyboardKey.home): DoNothingAndStopPropagationTextIntent(),
-    SingleActivator(LogicalKeyboardKey.end, control: true): DoNothingAndStopPropagationTextIntent(),
-    SingleActivator(LogicalKeyboardKey.home, control: true): DoNothingAndStopPropagationTextIntent(),
     SingleActivator(LogicalKeyboardKey.space): DoNothingAndStopPropagationTextIntent(),
     SingleActivator(LogicalKeyboardKey.enter): DoNothingAndStopPropagationTextIntent(),
   };
@@ -455,6 +445,16 @@ class DefaultTextEditingShortcuts extends StatelessWidget {
     const SingleActivator(LogicalKeyboardKey.arrowRight, shift: true, alt: true): const DoNothingAndStopPropagationTextIntent(),
     const SingleActivator(LogicalKeyboardKey.arrowLeft, shift: true, meta: true): const DoNothingAndStopPropagationTextIntent(),
     const SingleActivator(LogicalKeyboardKey.arrowRight, shift: true, meta: true): const DoNothingAndStopPropagationTextIntent(),
+    const SingleActivator(LogicalKeyboardKey.pageUp): const DoNothingAndStopPropagationTextIntent(),
+    const SingleActivator(LogicalKeyboardKey.pageDown): const DoNothingAndStopPropagationTextIntent(),
+    const SingleActivator(LogicalKeyboardKey.end): const DoNothingAndStopPropagationTextIntent(),
+    const SingleActivator(LogicalKeyboardKey.home): const DoNothingAndStopPropagationTextIntent(),
+    const SingleActivator(LogicalKeyboardKey.pageUp, shift: true): const DoNothingAndStopPropagationTextIntent(),
+    const SingleActivator(LogicalKeyboardKey.pageDown, shift: true): const DoNothingAndStopPropagationTextIntent(),
+    const SingleActivator(LogicalKeyboardKey.end, shift: true): const DoNothingAndStopPropagationTextIntent(),
+    const SingleActivator(LogicalKeyboardKey.home, shift: true): const DoNothingAndStopPropagationTextIntent(),
+    const SingleActivator(LogicalKeyboardKey.end, control: true): const DoNothingAndStopPropagationTextIntent(),
+    const SingleActivator(LogicalKeyboardKey.home, control: true): const DoNothingAndStopPropagationTextIntent(),
   };
 
   // Hand backspace/delete events that do not depend on text layout (delete