fix: revert key events to raw key events on Linux (#9161)

Signed-off-by: fufesou <linlong1266@gmail.com>

flutter/lib/common/widgets/remote_input.dart

@@ -27,6 +27,10 @@ class RawKeyFocusScope extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
+    // https://github.com/flutter/flutter/issues/154053
+    final useRawKeyEvents = isLinux && !isWeb;
+    // FIXME: On Windows, `AltGr` will generate `Alt` and `Control` key events,
+    // while `Alt` and `Control` are seperated key events for en-US input method.
     return FocusScope(
         autofocus: true,
         child: Focus(
@@ -34,7 +38,14 @@ class RawKeyFocusScope extends StatelessWidget {
             canRequestFocus: true,
             focusNode: focusNode,
             onFocusChange: onFocusChange,
-            onKeyEvent: (node, event) => inputModel.handleKeyEvent(event),
+            onKey: useRawKeyEvents
+                ? (FocusNode data, RawKeyEvent event) =>
+                    inputModel.handleRawKeyEvent(event)
+                : null,
+            onKeyEvent: useRawKeyEvents
+                ? null
+                : (FocusNode node, KeyEvent event) =>
+                    inputModel.handleKeyEvent(event),
             child: child));
   }
 }