Handle extractVolumePath() being null.

In some situations, the data path being migrated may not actually
be a valid /storage/ path, in which case we should gracefully
continue the migration flow without attempting a rename for pending
or trashed items.

Bug: 153825968
Test: atest --test-mapping packages/providers/MediaProvider
Change-Id: I3e4808b369f34d11797793e938ad61596dbc60fe
1 file changed