Backport of docs: document behaviour of tls.https.verify_outgoing into release/1.12.x

[hc-github-team-consul-core]

Backport

This PR is auto-generated from #20555 to be assessed for backporting due to the inclusion of the label backport/1.12.

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

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At first it's not clear what verify_outgoing would do for the https listener as it seems like Consul agent's don't make https requests. Upon further investigation, it's clear that Consul agents do make https requests in the following scenarios:

• to implement watches
• to perform checks

In the first scenario, this setting is used here: https://github.com/hashicorp/consul/blob/a1c8d4dd19caad13edf2d86441d1b7f9bbdc9c34/agent/config/runtime.go#L1725

In the second scenario, it's actually the internal_rpc setting that is used: https://github.com/hashicorp/consul/blob/a1c8d4dd19caad13edf2d86441d1b7f9bbdc9c34/tlsutil/config.go#L903

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Overview of commits

• ded3c9fa120058b1277f0407eae850a2b171c63a - f6ce7c35294889f1e3d17e448a59adfca95a89c4

[hc-github-team-consul-core]

🤔 This PR has changes in the website/ directory but does not have a type/docs-cherrypick label. If the changes are for the next version, this can be ignored. If they are updates to current docs, attach the label to auto cherrypick to the stable-website branch after merging.

[github-actions[bot]]

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[lkysow]

Closing because not critical this makes it into 1.12.x docs.