Remove list of OpenSource repos

[sdwheeler]

This PR removes the list of repositories that are configured to use the OpenSource user feedback experience. We shouldn't publish a list like this for the following reasons:

• The current list is out of date and it's too hard to maintain the list.
• The configuration is at the docset level not the repo level. A repo can have multiple docsets.
• Within a docset, you can limit the OpenSource to specific folders. For example, the dotnet/docs repo uses Standard feedback for some folders and OpenSource for others.
• The customer doesn't know or care about which repos are configured. They only know what they see on the web page.
• If the OpenSource feedback control exists on the bottom of the page, then the user can use it. If its not there, then they can't. Knowing the repo name is not helpful.

[learn-build-service-prod]

Learn Build status updates of commit e5ca01b:

✅ Validation status: passed

File	Status	Preview URL	Details
Contribute/content/provide-feedback.md	✅Succeeded	View

For more details, please refer to the build report.

For any questions, please:

• Try searching the learn.microsoft.com contributor guides
• Post your question in the Learn support channel

[sdwheeler]

#sign-off