Bump third_party/ot-br-posix/repo from `5417069` to `bfbd313` #1622

Job	Run time
REPL Tests - Linux	25m 6s
Test Suites - Darwin (no-ble-asan-clang)	1h 31m 22s
Test Suites - Linux (no-ble-tsan-clang)	1h 32m 18s
REPL Tests - Darwin	0s
	3h 28m 46s

Provide feedback