Bump third_party/libwebsockets/repo from `a1cbc02` to `816544f` #78228

Job	Run time
Unit / Integration Tests (main)	19m 45s
Unit / Integration Tests (clang)	16m 14s
Unit / Integration Tests (mbedtls)	25m 8s
Unit / Integration Tests (rotating_device_id)	18m 21s
	1h 19m 28s

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