Handle stopped state in SyncManager.

Ignore any new syncs (one-time and periodic) which are scheduled when
the package is in a stopped state.
The execution of already scheduled syncs for packages in a stopped state
will be handled by JobScheduler separately.

Bug: 209852664
Test: CtsSyncManagerTest
Change-Id: Ief61873b5fec500ee0d4d0d4a407f65d657d36ba
4 files changed