Fix isolated storage permission check.

We've already tested enough; no need to fall through to legacy
permission checks.

Bug: 117932814
Test: atest MediaProviderTests
Test: atest cts/tests/tests/media/src/android/media/cts/MediaScanner*
Test: atest cts/tests/tests/provider/src/android/provider/cts/MediaStore*
Change-Id: I94724d7ef0ae9a944455e9231a2e0081f33db052
1 file changed