Fix IME not shown from recents to split-screen task

DislplayImeController only update the ImeSurfaceControl
for a non-null control. So it still keep a stale control
even the control has lost.

The ImeSurfaceControl should be updated to avoid using a
stale control to start animation.

Bug: 258814082
Test: Manual test with bug steps
Test: atest DisplayImeControllerTest
Change-Id: Id7ac6de6a9e8e5f0e620254c39d104272175b3a1