Fix long characteristic write concurrency bug.

Tag: #stability
Test: Bramble (pixel phone) with test app
Bug: 169559728
Ignore-AOSP-First: Current security annotation parity
Merged-In: I3e3a5ff0965c1ca4f79e70e6163bc5d6917edbd1

Change-Id: Ia2d821c5d34d8d035fbbb0b33b9bf4fc8c08b354
1 file changed