Reset scroll position for Brave overflow main menu when it's shown (#32323)

Resets the overflow main menu to the top every time is shown. Modifications are applied using bytecode manipulations as we needed to modify upstream class `AppMenuHandlerImpl`.

android/java/apk_for_test.flags

@@ -1066,6 +1066,17 @@
     *** mShareButton;
 }
 
+-keep class org.chromium.chrome.browser.ui.appmenu.AppMenuHandlerImpl {
+    public <init>(...);
+    *** mAppMenu;
+    *** mAppMenuDragHelper;
+    *** showAppMenu(...);
+}
+
+-keep class org.chromium.chrome.browser.ui.appmenu.BraveAppMenuHandlerImpl {
+    public <init>(...);
+}
+
 -keep class org.chromium.chrome.browser.ui.AdaptiveToolbarUiCoordinator {
     *** mContext;
     *** mActivityTabProvider;