HDMI: Check if DUT can redirect volume key events as <UCP>

If the CTS set-up contains an HDMI Stub instead of a TV sink with CEC
disabled, the device used by "STREAM_MUSIC" might be internal speaker
instead of HDMI_OUT. If this happens, Audio Service won't announce
HdmiControlService about the volume changes and therefore, the DUT is
not capable of redirecting volume key events as <User Control Pressed>
leading to test failures.

Test: run cts -m CtsHdmiCecHostTestCases
Bug: 320388559
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:d2982b7d4d281f6fadc873806a81f2762dadd23f)
Merged-In: I63fe030fa2f0aa50cd0200e4a345aa30504d4fd1
Change-Id: I63fe030fa2f0aa50cd0200e4a345aa30504d4fd1