Fix the logic about notifyImeHidden and removeImeSurface

This CL fixes 2 issues.

For b/263472769, this CL restores the logic in collectSourceControls,
that when a type is requested to hide, we will let its consumer know, so
that it will have a chance to notify the remote control target. Also,
when IME is not ready, we only delayed the requested visibilities for
the types ready. In this way, the client can still send the requested
visibilities and notifyImeHidden to the server in split-screen mode,
when the client doesn't have the control.

For b/263345079, this CL refines the logic about handling pending
request in ImeInsetsSourceConsumer. If there is an opposite request
against to current animation, we won't remove the IME surface when
current animation ends.

Fix: 263472769
Fix: 263345079
Test: 1. Test if IME can be hidden by API in split-screen.
      2. atest ImeOpenCloseStressTest
Change-Id: I59952623bd0914aa236bd8f421c958f167cca63d