Ensure transaction is applied if added after SSG is complete

If a caller adds a Transaction to a SSG after its already complete, make
sure to immediately apply the Transaction and log a warning. It's better
for the Transaction to get applied instead of waiting around forever.

Also cleaning up some logs in SSG

Test: SurfaceSyncGroupTests
Bug: 272189296
Change-Id: I6810c5e0c20f3fd5c7d8bde16f24bc05a0495b4f