fix: make the message clearer when API key is missing #13251

Job	Run time
run ci on centos7 (lua-resty-worker-events, t/plugin/[a-k]*)	31m 52s
run ci on centos7 (lua-resty-worker-events, t/plugin/[l-z]*)	36m 3s
run ci on centos7 (lua-resty-worker-events, t/admin t/cli t/config-center-yaml t/control t/core t...	29m 7s
run ci on centos7 (lua-resty-worker-events, t/node t/pubsub t/router t/script t/secret t/stream-n...	24m 45s
run ci on centos7 (lua-resty-events, t/plugin/[a-k]*)	35m 10s
run ci on centos7 (lua-resty-events, t/plugin/[l-z]*)	35m 18s
run ci on centos7 (lua-resty-events, t/admin t/cli t/config-center-yaml t/control t/core t/debug ...	26m 30s
run ci on centos7 (lua-resty-events, t/node t/pubsub t/router t/script t/secret t/stream-node t/u...	26m 15s
	4h 5m 0s

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