feat: set default value of `ssl_trusted_certificate` to `system` #1167

Job	Run time
build (ubuntu-latest, linux_openresty, lua-resty-worker-events, t/http3/admin)	13m 34s
build (ubuntu-latest, linux_openresty, lua-resty-worker-events, t/plugin/[a-k]*)	18m 6s
build (ubuntu-latest, linux_openresty, lua-resty-worker-events, t/plugin/[l-z]*)	18m 7s
build (ubuntu-latest, linux_openresty, lua-resty-worker-events, t/admin t/cli t/config-center-yam...	18m 5s
build (ubuntu-latest, linux_openresty, lua-resty-worker-events, t/node t/pubsub t/router t/script...	18m 6s
build (ubuntu-latest, linux_openresty, lua-resty-events, t/http3/admin)	13m 54s
build (ubuntu-latest, linux_openresty, lua-resty-events, t/plugin/[a-k]*)	18m 5s
build (ubuntu-latest, linux_openresty, lua-resty-events, t/plugin/[l-z]*)	18m 6s
build (ubuntu-latest, linux_openresty, lua-resty-events, t/admin t/cli t/config-center-yaml t/con...	18m 5s
build (ubuntu-latest, linux_openresty, lua-resty-events, t/node t/pubsub t/router t/script t/secr...	18m 8s
	2h 52m 16s

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