Remove media.cas requirement.

This is a requirement on android phones and tv but
not on watches. Owner will handle putting that requirement
in place, but removing requirement from this file
specifically only in order to have O-MR1 interfaces
frozen.

Bug: 63603463
Test: m system_compatibility_matrix.xml compatibility_matrix.xml manifest.xml system_manifest.xml -j
Change-Id: Iefdc231c2928dfdb8e04a5de8a08ab9b23bae73d