Remove bubble button from desktop app menu

Desktop to bubble is not yet supported.

Bug: 406855697
Test: on tablet with desktop, check fullscreen task has bubble option,
  check that desktop task does not have bubble option
Flag: com.android.wm.shell.enable_bubble_to_fullscreen
Change-Id: Ie58490b4f5e156989e941ad48e4265f2b4f3beee