Bump third_party/libwebsockets/repo from `a1cbc02` to `816544f` #78227

Job	Run time
Unit / Integration Tests (main)	25m 51s
Unit / Integration Tests (clang)	15m 13s
Unit / Integration Tests (mbedtls)	21m 11s
Unit / Integration Tests (rotating_device_id)	25m 10s
	1h 27m 25s

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