fix: plugins cors allow_origins is "**" work does not meet expectations #16771

Job	Run time
build (ubuntu-20.04, linux_openresty, lua-resty-worker-events, t/plugin/[a-k]*)	35m 12s
build (ubuntu-20.04, linux_openresty, lua-resty-worker-events, t/plugin/[l-z]*)	33m 57s
build (ubuntu-20.04, linux_openresty, lua-resty-worker-events, t/admin t/cli t/config-center-yaml...	26m 17s
build (ubuntu-20.04, linux_openresty, lua-resty-worker-events, t/node t/pubsub t/router t/script ...	25m 42s
build (ubuntu-20.04, linux_openresty, lua-resty-events, t/plugin/[a-k]*)	32m 5s
build (ubuntu-20.04, linux_openresty, lua-resty-events, t/plugin/[l-z]*)	34m 24s
build (ubuntu-20.04, linux_openresty, lua-resty-events, t/admin t/cli t/config-center-yaml t/cont...	24m 50s
build (ubuntu-20.04, linux_openresty, lua-resty-events, t/node t/pubsub t/router t/script t/secre...	25m 34s
	3h 58m 1s

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