Backport of Add note about service upstream env var dot broken into release/1.17.x#19399

hc-github-team-consul-core wants to merge 2 commits intorelease/1.17.xhashicorp/consul:release/1.17.xfrom

backport/docs/note-about-connect-service-upstream-env-var/lively-exciting-reptilehashicorp/consul:backport/docs/note-about-connect-service-upstream-env-var/lively-exciting-reptileCopy head branch name to clipboard