Update action text for expanding or collapsing menu

When focusing on the app handle for a bubble, the talkback text for
click action said: "double-tap to activate". Same for the first item in
the menu.
These both items are used to either expand or collapse the menu.
Update the click action label for app handle to say "double-tap to
expand menu" and first menu item to say "double-tap to collapse menu".

Bug: 344674311
Flag: com.android.wm.shell.enable_bubble_bar
Test: focus on app handle for a bubble, check the talkback text for
  click action
Test: focus on first bubble handle menu item, check the talkback text
  for click action
Change-Id: Idec815c625eac49e74d2a8420cbc8ef6385f08cb