Disable 48.0kHz sampling rate for AAC - update the unit test

Some carkits have issues playing A2DP audio using AAC with 48.0kHz
sampling rate, while playing AAC with 44.1kHz sampling rate is fine.

Bug: 38443632
Bug: 62301376
Test: manual
Change-Id: I5a8b72e86fb1a2cbf92f85e7a6c340cee58dadb5