Report launch finish for drawn without transition

An activity can be launched and drawn without transition, e.g.
quick open camera from lockscreen, so the launch metrics can
be reported directly when it is drawn. Otherwise there may be
unexpected long trace and metric if the activity launches
another activity with transition after a while.

Bug: 204488635
Test: atest ActivityMetricsLaunchObserverTests# \
            testActivityDrawnWithoutTransition
Test: Enabled secured lock. Enter lock screen. Double press
      power key to launch camera. Wait 5s, click photo and
      unlock. The 5s should not count to photo (event log
      wm_activity_launch_time).

Change-Id: Ib47784bf5a83d6bec2271f85ed165f31784ce937