Fix connect as manager using recently deleted account

Use the new connection inside the try...except so that the RefreshError (or other HttpError) can be caught and the next manager can be tried.

Fill resolve: https://gitlab.developers.cam.ac.uk/uis/devops/gsuite/sync-deploy/-/jobs/967522

Local test result (failed for user failing in above pipeline then succeeding as a different manager):

INFO:gdrivemanager.gapi:Loading Google account credentials from ./credentials.json.
INFO:gdrivemanager.gapi:Getting storage quota usage for <REDACTED>@cam.ac.uk
INFO:gdrivemanager.gapi:Issuing request to Google.
WARNING:gdrivemanager.manage:Unable to connect as <REDACTED>@cam.ac.uk to get usage for shared drive '<REDACTED>' - '<REDACTED>'
INFO:gdrivemanager.gapi:Loading Google account credentials from ./credentials.json.
INFO:gdrivemanager.gapi:Getting storage quota usage for <REDACTED>@cam.ac.uk
INFO:gdrivemanager.gapi:Issuing request to Google.
INFO:gdrivemanager.manage:Getting usage for shared drive '<REDACTED>' as '<REDACTED>'