ut_ice_sdp_parser: rework test

Rework the test to use two audio streams instead of audio+video.
This is needed to run the test on environments where the camera
is not available (e.g. Docker). For this specific test, the media
type is irrelevant, so using two audio media is acceptable.

Gitlab: #516

Change-Id: Idc4911d5aea5ffdd931bd7d63516ed484344d41c