Updated fuzzers for libbt-audio-hal-interface

This patch updates fuzzers to only feed valid pcm parameters
to libbt-audio-hal-interface and add checks for successful completion
of a2dp::init() and a2dp::setup_codec() methods

Test: ./libbt_audio_hal_a2dp_encoding_fuzzer
exec/s for libbt_audio_hal_a2dp_encoding_fuzzer: 58
Test: ./libbt_audio_hal_le_audio_software_fuzzer
exec/s for libbt_audio_hal_le_audio_software_fuzzer: 72
Test: ./libbt_audio_hal_hearing_aid_software_encoding_fuzzer
exec/s for libbt_audio_hal_hearing_aid_software_encoding_fuzzer: 125
Test: ./libbt_audio_hal_client_interface_fuzzer
exec/s for libbt_audio_hal_client_interface_fuzzer: 95
Bug: 220381921
Bug: 220329620

Change-Id: Id4293d0ed44101081d576aa8fca61e43bf04139e