Make full syncs resumable

Previously, every time a full sync was triggered the database would get
reset. This would mean that instead of resuming a full sync, we would
always restart it.

With this change, we only restart the sync if the collection id or the
cloud provider has been changed.

Bug: 311851723
Test: atest PickerSyncControllerTest
Change-Id: I481b353442c02bed59779daa50be66688ce94b14
3 files changed