CastTile: UX fixes for media projection.

- Long clicks on the tile are handled the same way as clicks
  regardless of whether the tile is indicating an active media
  projection session or not.
- Regular clicks on the tile when a media projection session is
  active and the device is locked with a secure keyguard should
  stop the session (and not prompt the user to unlock).

Test: manual
Bug: 124753835
Change-Id: I4009563a49377734850b3da0ead3215721de7d22