Support setting BT controller Low Latency mode(1/2)

Handle audio api StartRequest and SetLatencyMode in a2dp to send stream latency
through btif_av to bta event.

Bug: 240637363
Bug: 223126227
Tag: #feature
Ignore-AOSP-First: TM QPR1 feature
Test: test on sink device support dynamic spatial audio
Change-Id: I9ad4a23a58eeca6128a9f04a530ae6c90c773da5