Suppress 'radio' processes to media.metrics

We suppress calls from radio processes (including the basic phone
process) to the media.metrics service. This had started happening
for a particular video telephony application that ran within phone
instead of as some separate app with its own user id.

We do this here to speed up when a radio process learns that it
can not log to media.metrics. The existing sepolicy restrictions
remain in place as a fallback. The use case that prompted this
was having issues with the 5-second timeout before we learned that
radio wasn't allowed access to the media.metrics process.

Bug: 37552329
Test: observe 'dumpsys media.metrics' and logcat
Change-Id: I1824aa35860bb91dd796856453c1897ec21b496c