Fix spammy invalid media capabilities uid log event

Previously, we logged if a non app uid is passed in a Bundle, but if
it's empty and we get 0, we think an invalid uid was passed.

Now, we check if the media_capabilities uid is present in the bundle
before attempting to extract/log invalid

Test: atest TranscodeTest
Bug: 176157500
Change-Id: Ia356dc59d97422dd5a9adf0f3da75f99cc78dd27
1 file changed