Downgrade compactions after throttle checks

This fixes a spammy log issue that happens every time a compaction is
requested independently of whether it would end up being discarded due
to throttles. Further inspection showed that based on the current
throttles moving it to happen post-throttles does not change behavior
as throttles work the same way for some and full compactions

Bug: 232567934
Test: am compact <pid> <uid> full
Change-Id: Ic886f889c5b8670637b9786112d94c6ad666e8bf