Fix typo in #48028

[anomiex]

Proposed changes

The file is mirrors.txt, not mirror.txt. 🤦

Fortunately it doesn't break anything.

Related product discussion/links

None

Does this pull request change what data or activity we track or use?

No

Testing instructions

• This time I ran a modified workflow in the fork that actually hits this code (but just cats the file instead of trying to push to any mirrors): https://github.com/anomiex/jetpack/actions/runs/24210037027/job/70678101689

[github-actions]

Are you an Automattician? Please test your changes on all WordPress.com environments to help mitigate accidental explosions.

• To test on WoA, go to the Plugins menu on a WoA dev site. Click on the "Upload" button and follow the upgrade flow to be able to upload, install, and activate the Jetpack Beta plugin. Once the plugin is active, go to Jetpack > Jetpack Beta, select your plugin (Jetpack or WordPress.com Site Helper), and enable the fix/typo-in-48028 branch.
• To test on Simple, run the following command on your sandbox:

bin/jetpack-downloader test jetpack fix/typo-in-48028

bin/jetpack-downloader test jetpack-mu-wpcom-plugin fix/typo-in-48028

Interested in more tips and information?

• In your local development environment, use the jetpack rsync command to sync your changes to a WoA dev blog.
• Read more about our development workflow here: PCYsg-eg0-p2
• Figure out when your changes will be shipped to customers here: PCYsg-eg5-p2

[github-actions]

Thank you for your PR!

When contributing to Jetpack, we have a few suggestions that can help us test and review your patch:

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• ✅ Add changelog entries to affected projects
  

This comment will be updated as you work on your PR and make changes. If you think that some of those checks are not needed for your PR, please explain why you think so. Thanks for cooperation 🤖

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[tbradsha]

Ha, oops!