Add troubleshoot help to install NuGet packages

[rafaelschlatter]

Why:

Closes #19541 The documentation on how to install NuGet packages from GitHub packages is missing an important point. If installing a NuGet package from a different repository, authentication using a GITHUB_TOKEN in the GitHub action will fail. A personal access token (PAT) needs to be used instead. Closes issue #19541 .

What's being changed (if available, include any code snippets, screenshots, or gifs):

Added an additional bulletpoint in the "Troubleshooting" section. It explains how to authenticate within a GitHub action when installing a NuGet package from a different repository.

Check off the following:

• [x] I have reviewed my changes in staging (look for the "Automatically generated comment" and click the links in the "Preview" column to view your latest changes).
• [x] For content changes, I have completed the self-review checklist.

Writer impact (This section is for GitHub staff members only):

• [ ] This pull request impacts the contribution experience
  • [ ] I have added the 'writer impact' label
  • [ ] I have added a description and/or a video demo of the changes below (e.g. a "before and after video")

[welcome[bot]]

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[github-actions[bot]]

Automatically generated comment ℹ️

This comment is automatically generated and will be overwritten every time changes are committed to this branch.

The table contains an overview of files in the content directory that have been changed in this pull request. It's provided to make it easy to review your changes on the staging site. Please note that changes to the data directory will not show up in this table.

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Content directory changes

You may find it useful to copy this table into the pull request summary. There you can edit it to share links to important articles or changes and to give a high-level overview of how the changes in your pull request support the overall goals of the pull request.

Source	Preview	Production	What Changed
packages/working-with-a-github-packages-registry/working-with-the-nuget-registry.md	fpt ghec ghes@ 3.6 3.5 3.4 3.3 3.2 ghae	fpt ghec ghes@ 3.6 3.5 3.4 3.3 3.2 ghae

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fpt: Free, Pro, Team ghec: GitHub Enterprise Cloud ghes: GitHub Enterprise Server ghae: GitHub AE

[cmwilson21]

@rafaelschlatter Thanks for opening an issue and a PR! ✨ I edited your post slightly just so it connects to your issue.

I'll get this triaged for review! ⚡

[vgrl]

Thanks for this contribution @rafaelschlatter! ⚡ Earlier in the same article, in the "Authenticating to GitHub Packages" section, we already mention the limitation of using the GITHUB_TOKEN, however I agree it may assist other users to also mention this in the "Troubleshooting" section towards the end of the article.

As such I'm going to make a few changes to your proposed language, and then I'll merge this.

[github-actions[bot]]

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