Bump third_party/ot-br-posix/repo from `bd15f71` to `9ca3b36` #393

Job	Run time
Unit / Integration Tests (main)	20m 36s
Unit / Integration Tests (clang)	23m 8s
Unit / Integration Tests (mbedtls)	17m 21s
Unit / Integration Tests (rotating_device_id)	15m 42s
Unit / Integration Tests (icd)	50m 44s
	2h 7m 31s

Provide feedback