(MAINT) Add echo to live branch check

[michaeltlombardi]

PR Summary

This commit adds an echo to the GHA for validating that a PR author has authorization
to submit a PR to the Live branch. It reports the username and discovered permissions
before echoing that the author has permissions or throwing if they do not.

PR Context

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Repository or docset configuration

• Repo documentation and configuration (.git/.github/.vscode etc.)
• Docs build files (.openpublishing.* and build scripts)
• Docset configuration (docfx.json, mapping, bread, module folder)

Conceptual documentation

• Files in docs-conceptual

Cmdlet reference & about_ topics
When changing cmdlet reference or about_ topics, the changes should be copied to all
relevant versions. Check the boxes below to indicate the versions affected by this change.

• Preview content
• Version 7.2 content
• Version 7.1 content
• Version 7.0 content
• Version 5.1 content

PR Checklist

• I have read the contributors guide and followed the style and process guidelines
• PR has a meaningful title
• PR is targeted at the staging branch
• All relevant versions updated
• Includes content related to issues and PRs - see Closing issues using keywords.
• This PR is ready to merge and is not Work in Progress. If the PR is work in progress,
  please add the prefix WIP: or [WIP] to the beginning of the title and remove the prefix when
  the PR is ready.

[opbld33]

Docs Build status updates of commit 0902dcd:

✅ Validation status: passed

File	Status	Preview URL	Details
.github/workflows/targeting-valid-branch.yml	✅Succeeded

For more details, please refer to the build report.

Note: Broken links written as relative paths are included in the above build report. For broken links written as absolute paths or external URLs, see the broken link report.

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