Rate limit BR notifications

To avoid notifications throttling, rate limit the notifications
instead of delaying the final notification. The final delay doesn't
worj in case the service get's killed, which can happen on a busy
device. Note, this is in control of the system and not the 
service/client.

Bug: 395488230
Change-Id: I9fb20868e163292c7e12c5cc12c4e79c7683aab9
Test: N/A couldn't repro
Flag: EXEMPT Minor Change