When testing the granular consent screen that Google will very soon be enforcing we have noticed that if a user attempts to upload a file from google drive and has not previously authenticated against moodle with oauth and does not tick the box to grant consent to access google drive then they are given a missing scopes error with no user friendly explanation or steps to rectify it. 

I think it would be a huge improvement if there was simply an option to reauthorise and grant that permission

Steps to reproduce:

1. Add enable_granular_consent=true to "Additional parameters included in a login request" in the Google OAuth configuration 
2. Open the file picker and select Google Drive and authenticate with an account that has never been authorised with the moodle instance before
3. Do not select to grant permission to Google drive and continue 
4. A missing scopes exception is thrown
5. Refresh and try again and the exception is thrown again with no option to reauthorise