Make CAPTURE_SECURE_VIDEO_OUTPUT privileged again

a69e3678 restricted
CAPTURE_SECURE_VIDEO_OUTPUT to signature only. This breaks
casting premium content from Play Apps & Movies and YouTube
app.

Revert the restriction for now while we figure out the right
thing to do.

BUG: 114183892
BUG: 111131054
Test: Tested by mirroring the device to chromecast and verified
playing premium content on Play Movies & TV app and YouTube
works correctly.

Change-Id: Ifb247c17be924655d7fc95b7e957f9822254d363