chore: remove `core.grpc` module (#11427) #20

Job	Run time
build (ubuntu-20.04, linux_openresty, lua-resty-worker-events, t/http3/admin)	15m 0s
build (ubuntu-20.04, linux_openresty, lua-resty-worker-events, t/plugin/[a-k]*)	30m 22s
build (ubuntu-20.04, linux_openresty, lua-resty-worker-events, t/plugin/[l-z]*)	30m 22s
build (ubuntu-20.04, linux_openresty, lua-resty-worker-events, t/admin t/cli t/config-center-yaml...	28m 4s
build (ubuntu-20.04, linux_openresty, lua-resty-worker-events, t/node t/pubsub t/router t/script ...	25m 36s
build (ubuntu-20.04, linux_openresty, lua-resty-events, t/http3/admin)	15m 49s
build (ubuntu-20.04, linux_openresty, lua-resty-events, t/plugin/[a-k]*)	29m 21s
build (ubuntu-20.04, linux_openresty, lua-resty-events, t/plugin/[l-z]*)	27m 41s
build (ubuntu-20.04, linux_openresty, lua-resty-events, t/admin t/cli t/config-center-yaml t/cont...	25m 30s
build (ubuntu-20.04, linux_openresty, lua-resty-events, t/node t/pubsub t/router t/script t/secre...	25m 37s
	4h 13m 22s

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