Fix remote input view clobbering

- If a notification is updated, make sure that the focus
  is kept even when the change cannot be applied inline.
- Make sure to update the pending intent to match one
  of the new actions in case the old one is no longer
  valid, and to prevent sending text to the wrong action
  unintentionally.
- Keep focus when switching between heads-up and expanded.
- Prevent the action container from becoming transiently
  gone during reapplying.

Fixes: 27357771
Change-Id: Ie9f49935827f6efb15b73f8d686f0c110448456a