fix: plugins cors allow_origins is "**" work does not meet expectations #16778

Job	Run time
build (ubuntu-20.04, linux_openresty, lua-resty-worker-events, t/plugin/[a-k]*)	34m 54s
build (ubuntu-20.04, linux_openresty, lua-resty-worker-events, t/plugin/[l-z]*)	33m 15s
build (ubuntu-20.04, linux_openresty, lua-resty-worker-events, t/admin t/cli t/config-center-yaml...	24m 33s
build (ubuntu-20.04, linux_openresty, lua-resty-worker-events, t/node t/pubsub t/router t/script ...	28m 27s
build (ubuntu-20.04, linux_openresty, lua-resty-events, t/plugin/[a-k]*)	32m 58s
build (ubuntu-20.04, linux_openresty, lua-resty-events, t/plugin/[l-z]*)	33m 6s
build (ubuntu-20.04, linux_openresty, lua-resty-events, t/admin t/cli t/config-center-yaml t/cont...	25m 26s
build (ubuntu-20.04, linux_openresty, lua-resty-events, t/node t/pubsub t/router t/script t/secre...	26m 46s
	3h 59m 25s

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