Allow permission pre-grant files on OEM partition

If there are apps on /oem, permission pregrant xmls should
be there too. Remove the old embedded check that stopped
oem pre-grants.

Test: Add pre-grant xml on /oem and check in Settings
Bug: 300042518
Change-Id: Id50c1d77f12734f044b221f80a39f3c253fa51fb
1 file changed