Fine-grained PATs can access `internal` repos [GA]

### Value Prop

Users will be able to use fine-grained PATs (Personal Access Tokens) to access `internal` repositories in their enterprises, even without targeting the organization that owns the repository. This helps scripts pull down required resources from across the enterprise using a single token.

### Expected Outcome

Fine-grained PATs need to support all of the same use cases as PATs (Classic), including their use in inner source scenarios. With this gap closed, more developers should be able to use the more secure fine-grained PATs system for their work.