Improve Verbiage When Trying to Create a Workspace from an Organization in GitHub

This was originally reported in a support ticket. I see we have some documentation in regards to this specific issue but I believe we have an opportunity here to improve the error message shown to the user when they try creating a workspace from a private repository in an organization.

Perhaps we can include a link to the above documentation or show the steps necessary to resolve this right within the error message. The error message shown to the user is:

Repository not found. (organization/repository) Your access token was updated recently. Please try again if the repository exists and Gitpod was approved for Organization.

I've replaced some of the text above - organization/repository, but the message is otherwise the same.

Front conversations

Start with the workspace-creation flow for private repositories in GitHub organizations and compare its error handling with the linked documentation on private repositories. Update the message to provide clearer recovery guidance, either by linking that documentation or including its steps, and verify the resulting message for the reported organization/repository case.