Run expiration when rollback lifetime is changed. DO NOT MERGE

See b/151890602#comment6 for the detail.

When rollback lifetime is changed, we need to re-schedule the
expiration algorithm so rollbacks can expire at the correct time.

Note we combine #runExpiration and #scheduleExpiration so there is only
one entrance to schedule the expiration algorithm.

See
https://googleplex-android-review.git.corp.google.com/c/platform/frameworks/base/+/10899294/1/services/core/java/com/android/server/rollback/RollbackManagerServiceImpl.java#672
for the rationale.

Bug: 151890602
Test: atest RollbackTest
Change-Id: I10355143dedc0af92e0b2adfedb5f008e160cbb3