Ignore setForegroundAllowance calls in case of MediaSession2

- For an app to fullfill FGS requirements, it needs to have a
user-engaged media session that is linked to a media style notification.

- Currently notifications can't be linked to a MediaSession2, so we
don't report the changes in user engagement in cases of MediaSession2.

Bug: 295518668
Test: Non functional change for non MediaSession2 cases.
Change-Id: Iae81139a20b39e9f59dfacc43512a00c7abd8f05