Bump third_party/ot-br-posix/repo from `8299da3` to `636e53d` #599

Job	Run time
Unit / Integration Tests (main)	20m 16s
Unit / Integration Tests (clang)	16m 14s
Unit / Integration Tests (mbedtls)	18m 24s
Unit / Integration Tests (rotating_device_id)	17m 14s
	1h 12m 8s

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