Add removal time of starting window in transition trace proto

The transition can play with the starting window, and even if the
transition is finished, the app window may still not draw yet.
Then at the timestamp of removing the starting window, this log
can provide the info for flicker detection to check that the app
is drawn or not.

Bug: 284302118
Test: The app surface is visible at timestamp of remove_time_ns
Change-Id: I869b5a1213b7b64c4a875a9ac33c8245fcccf40f