In prepare_withSupportedTrack_sendsPlayRequest(), the DESCRIBE includes two
tracks, one AAC and one MP4A-LATM. The test is run until a PLAY is sent, and
asserts on only one SETUP is sent (for AAC).
In prepare_noSupportedTrack_throwsPreparationError(), the DESCRIBE includes one
track: one MP4A-LATM. This format is not supported at the moment, so the player
will throw out an error, on which we assert.
PiperOrigin-RevId: 380131458
