Post the mSearchUiManager.resetSearch() to next frame.

SearchBox gets cleared in the current frame even before we read the
input entered by the user. So clear the searchbox in next frame after
onAllAppsTransitionEnd is completed.

See ag/22266746 where this change was introduced and I want to move the resetSearch() call to next frame.

Bug: 287693114
Test: Manual . Tested with both Floating search box on and off.
Flag: NA

Change-Id: I11509cf652f96847ad3c54f20a76f2a728775fe3