Added user role to captured Sentry data

closes https://github.com/TryGhost/Team/issues/2241

- as part of the authenticated application setup, update the captured Sentry data with the user role
- helps narrow things down when we see permission errors pop up due to requests being made for endpoints that the current user doesn't have permission to access

ghost/admin/app/services/session.js

@@ -54,7 +54,8 @@ export default class SessionService extends ESASessionService {
                     return new Promise((resolve) => {
                         resolve({
                             ...event,
-                            release: `ghost@${this.config.version}`
+                            release: `ghost@${this.config.version}`,
+                            'user.role': this.session.user.role.name
                         });
                     });
                 });