Backport of Fix Backport Assistant PR commenting into release/1.16.x

[hc-github-team-consul-core]

Backport

This PR is auto-generated from #18200 to be assessed for backporting due to the inclusion of the label backport/1.16.

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

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For general comments on a PR, it looks like you have to use the /issue endpoint rather than /pulls, which requires commit/other review-specific target details.

This matches the endpoint used in backport-reminder.yml.

Also remove the noisier Backport Reminder workflow in favor of recent automation to assign backport PRs to authors.

Description

Follow-up to #17197, plus a noise-reduction fix.

Testing & Reproduction steps

Ran:

github_message="Backport failed @zalimeni. Run: [this is a test to fix broken commenting, no link included]"
          curl -s -H "Authorization: token ${PR_COMMENT_TOKEN}" \
            -X POST \
            -d "{ \"body\": \"${github_message}\"}" \
            "https://api.github.com/repos/hashicorp/consul/issues//comments"

and it worked. (I also fat-fingered the PR I meant to target the first time 😛)

PR Checklist

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

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Overview of commits

• de63f65 - f6c0fff

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

Auto approved Consul Bot automated PR