Prepare to clean up the drawing snapshot with aspect ratio mismatch

Core won't ask to draw snapshot window if the aspect ratio isn't match.
Add a flag to verify if it is safe to delete.

Flag: com.android.window.flags.draw_snapshot_aspect_ratio_match
Bug: 341020277
Test: presubmit

Change-Id: I3e2b3435ba2ffe60c90c22ed563435e0c1e781d7