audio_hal/aidl: Don't fallback to SW encoding when HW is supported

The following commit:

 29d38ad3 Add support for Opus in BT Audio HAL

Added
BTAV_A2DP_CODEC_INDEX_SOURCE_LC3
BTAV_A2DP_CODEC_INDEX_SOURCE_OPUS
BTAV_A2DP_CODEC_INDEX_SINK_OPUS
to the available codecs.

This causes UpdateOffloadingCapabilities to return early with failure
when handling BTAV_A2DP_CODEC_INDEX_SOURCE_LC3 which casues fallback
to SW encoding even when other codecs than lc3 is available for HW
offloading. Also add case for BTAV_A2DP_CODEC_INDEX_SINK_OPUS for
completeness.

The following can be observed in the log:
[ERROR:codec_status_aidl.cc(558)] UpdateOffloadingCapabilities: Unknown codec_type=5

Test: See issue
Bug: 266208838
Change-Id: I7b145a6f74a3540ca2083630afb97fcc154c841d