leaudio: Fix possible race on start stream request from HAL am: 124fb75a am: db3021d7

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Bluetooth/+/2962588



Change-Id: I9e9dacea5367b77a6110c2e32c43b52fe2d67d34
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>