Don't carry out resuming activity in TaskFragment if not ready.

This is checked at ActivityTaskSupervisor, but by that point it is possible all the TaskFragment states have been updated, and so the next time attempting to resume will just no-op. Instead we should exit early if we have signal to defer resume until later.

Test: atest
android.server.wm.activity.lifecycle.ActivityLifecycleTopResumedStateTests#testTopPositionLaunchedBehindLockScreen
Bug: 385864843
Flag: com.android.window.flags.ensure_keyguard_does_transition_starting

Change-Id: I3af7401e5ec1e2379ce5cb74df8c81547ec4ceb2