mediav2: Remove vp9 profile workaround for high bit depth clips

Webm extractor wasn't signaling profile for some clips earlier.
It is now updated to synthesize VP9 profile and signal it as expected.

Bug: 295804596
Test: atest CtsMediaV2TestCases -- --module-arg \
CtsMediaV2TestCases:instrumentation-arg:codec-prefix:=c2.android.vp9

Change-Id: I5affcb28512cc71329bd0df2e74d614734e7be4f