Add help on getting permissions to add labels to Spec PRs in Next Steps comment

In the public repo we require the service team to add "PublishToCustomers" on PRs to acknowledge that merge to main means the REST API is ready to release to customers. But some service teams report that they are not allowed to add labels to PRs. Maybe they need to join the Azure GitHub org or something? It would be good to include information on how to get permission to add labels, even if it is just a link off to somewhere, in the "Next Steps to Merge" message about the missing "PublishToCustomers" label:


Locate the automation that generates the "Next Steps to Merge" comment when the "PublishToCustomers" label is missing. Start by tracing that message and identify where its guidance is defined; done means the comment explains how service teams can obtain permission to add the label, including the relevant link if one is available.

Written by the indexing model from the issue text.