Backport of Update service-defaults.mdx into release/1.15.x

[hc-github-team-consul-core]

Backport

This PR is auto-generated from #17656 to be assessed for backporting due to the inclusion of the label backport/1.15.

🚨

Warning automatic cherry-pick of commits failed. If the first commit failed,
you will see a blank no-op commit below. If at least one commit succeeded, you
will see the cherry-picked commits up to, not including, the commit where
the merge conflict occurred.

The person who merged in the original PR is:
@im2nguyen
This person should manually cherry-pick the original PR into a new backport PR,
and close this one when the manual backport PR is merged in.

merge conflict error: unable to process merge commit: "6651b2de39dfcaa013f5ac2e72fe541ca1efccb7", automatic backport requires rebase workflow

The below text is copied from the body of the original PR.

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Description

when using service-defaults for external services, if the client is dialing an HTTPS (encrypted) traffic, protocol should be set to TCP and port 443.

Testing & Reproduction steps

PR Checklist

• updated test coverage
• external facing docs updated
• appropriate backport labels added
• not a security concern

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Overview of commits

• 9ec2b38 - 6651b2d

[github-team-consul-core-pr-approver]

Auto approved Consul Bot automated PR