Fix CTS KeyEventTest

As part of the microphone mute implementation, KEYCODE_MUTE is no
longer considered a media key; unfortunately, the CTS test for it
was not changed accordingly, so this CL resolves that.

Bug: 255649498
Test: KeyEventTest must pass
Change-Id: I2b98500f9b4c79cf5a3dd795f6ffe551ae4107c8
1 file changed