Android new tab at the bottom (#35051)

* [Android] Move tab switcher controls to bottom when address bar is at bottom

When the address bar is configured to show at the bottom, reposition the
entire hub toolbar (new tab, menu, pane switcher, search, shred) from
the top to the bottom of the tab switcher for one-handed accessibility.

- BraveHubManagerImpl: Add maybeRepositionToolbarToBottom() that changes
  the toolbar wrapper's FrameLayout gravity to BOTTOM and swaps the pane
  host container's top margin to bottom margin. Uses EdgeToEdge pad
  adjuster (same pattern as upstream HubBottomToolbarCoordinator) to
  handle navigation bar insets. Properly cleans up the adjuster on hub
  hide since the coordinator and views are destroyed between show/hide
  cycles.

- BraveHubManagerImplClassAdapter: Expose parent's mEdgeToEdgeSupplier
  field via deleteField/makeProtectedField bytecode pattern.

- BraveToolbarManager: Remove setLayoutStateProvider() and its
  LayoutStateObserver that toggled menu popup direction on tab switcher
  transitions. No longer needed since the hub toolbar is now at the
  bottom when address bar is at bottom.

- BraveHubToolbarView: Change INVISIBLE to GONE for hidden action/menu
  buttons when bottom navigation controls are enabled (address bar on
  top). INVISIBLE left the buttons clickable despite being hidden.

Resolves: https://github.com/brave/brave-browser/issues/53326

android/java/apk_for_test.flags

@@ -908,6 +908,7 @@
 
 -keep class org.chromium.chrome.browser.hub.HubManagerImpl {
     *** ensureHubCoordinatorIsInitialized(...);
+    *** mEdgeToEdgeSupplier;
 }
 
 -keep class org.chromium.chrome.browser.ui.system.StatusBarColorController {