In this PR, I'm doing 2 things:
- refresh connectedAccount token on message-list-fetch. It's currently
only refresh while doing the messages-import. However messages-import
stage are only triggered if new messages are detected (which could take
days or week depending of the messageChannel activity). We should also
refresh it while trying to fetch the list
- handle Unhandled Gmail error code 500 with reason "backendError".
These can occur on gmail side. In this case, we just retry later.
3c5a4ba692