Block write access to media for non-owners.

The new security model in Q requires that apps can't directly write
to media they don't own.  They can still gain write access using
RecoverableSecurityException.

Bug: 130367350
Test: atest --test-mapping packages/providers/MediaProvider
Exempt-From-Owner-Approval: trivial test change
Change-Id: I0b89e29eb6b70309e9e318606598f1ef774fcd23
1 file changed