Fix BTA_AV_API_SET_LATENCY_EVT not handled

BTA_AV_API_SET_LATENCY_EVT is the last AV event enum item.
Modified BTA_AV_LAST_NSM_EVT and BTA_AV_LAST_NSM_EVT to
BTA_AV_API_SET_LATENCY_EVT.

Bug: 240637363
Bug: 223126227
Tag: #feature
Ignore-AOSP-First: TM QPR1 feature
Test: test on sink device support dynamic spatial audio
Change-Id: I1e547456d073dbb0cef2233e0d6806b405aaae37