Do not allow focus on handle when menu is open

Do not allow talkback to focus on app handle when the menu is open.
The handle is not clickable with touch, ensure it is the same with
talkback.

Bug: 344674311
Flag: com.android.wm.shell.enable_bubble_bar
Test: expand menu from app handle, swipe to next element and check that
  focus never shifts to the handle
Change-Id: I8064f79368e8a706f48eca7050b096cfbc849398