Add feature flag CrOSLateBootBluetoothAudioLEAudioOnly

This CL adds the feature flag.

BUG=b:317683550
TEST=CQ

Change-Id: I37532be30c37d72794ee68f75093eb2478b26277
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5401303


Reviewed-by: Li-Yu Yu <aaronyu@google.com>
Reviewed-by: Ching Yun Chang <whalechang@google.com>
Commit-Queue: Jeremy Wu <jrwu@google.com>
Cr-Commit-Position: refs/heads/main@{#1280047}