Add enter reasons for split screen sources

* LAUNCHER reason means that the source
is also being logged by launcher, and the
instanceID should be used to join events
from launcher logging to determine the specific
source

Bug: 231369744
Change-Id: Ic4357dd790094dd9c8208d7c500c8dc82432c054
Merged-In: Ic4357dd790094dd9c8208d7c500c8dc82432c054