Call persistToDisk after indexing VisibilityDoc

In ag/13985751 [e62a4eb007fc0266be6955c837d188a204c11cc2], we added calls to persist LITE after each mutation api
call. However, VisibilityStore also creates a mutation in Icing lib - it
indexes a single VisibilityDoc. We should also call persist LITE after
this so that we can be sure not to lose the VisibilityDoc.

Bug: 180127220
Test: None

Change-Id: Ib8465a3b2f4adb8f4dc4308c3845fcc501f36c0b
1 file changed