When PR creation fails due to OAuth App access restrictions provide a useful user error

[krlvi]

The following errors:

Although you appear to have the correct authorization credentials, the XXX organization has enabled OAuth App access restrictions, meaning that data access to third-parties is limited

are related to the config on github's org side. If that occurs the app should provide a helpful error message (+ link to docs for what can be done)

[gregkonush]

not clear what needs to be done at that when organization permissions are not there