Rollback package after reboot has been performed

As rollback involves reverting back to an older version, it should be higher user impact than just reboot. Also, since rolling back package anyways require reboot, reboot is redundant step for fixing after rollback. Hence increasing the impact level for rolling back package.

Test: atest RollbackPackageHealthObserverTest
Bug: b/278707946
Change-Id: I76dac653b4ca3a97be1f9906b27d2f65986326af