Avoid calling syncInputTransactions within wm lock

It is possible to block wm lock for 5 seconds, waiting for sync
input transaction.

Also avoid move focus to the adjacent embedded window when the
adjacent activity is not yet visible.

Bug: 436971500
Test: TaskFragmentTest
Flag: EXEMPT bugfix
Change-Id: I5d30f8f29514a49633d846824bc7565dc7083f0e