Support re-attaching the inline suggestion view to window

* Before this change, when the inline suggestion view is detached from
  the IME window (e.g. due to layout change), the remote view content
  will not show again even after the view is reattached to the window
  on the IME side. This patch fixes it by requesting the remote view
  owner (the ext services) for a new SurfacePackage when the view is
  re-attached to the window (see javadoc of SurfaceControlViewHost for
  why this works).
* This patch also fixes the issue where the SurfaceControlViewHost was
  never released in the ext services. This is done by notifying the
  ext services (through system server) when the view is detached from
  the IME window, and then the system server will release the
  SurfaceControlViewHost if after N(=500) ms the view is not re-attached
  to a window.
* After the SurfaceControlViewHost is released, if the view is
  re-attached to the window later, a new SurfaceControlViewHost will be
  created to back the same InlineContentView.
* The current code structure also lays a foundation for a subsequent
  change to allow reusing the same remote view for inline suggestions
  during filtering.

Test: atest CtsAutofillServiceTestCases (sanity test)

Bug: 153615023
Bug: 154683107

Change-Id: Idc587e1e82a96b792c351796464821b7aad7cd89