Remove unnecessary cache refreshes from the Google Contacts backend

Remove unnecessary cache refreshes from the Google Contacts backend

We shouldn't refresh the cache immediately after authenticating for two
reasons:
 • If it fails, its error gets conflated with any errors from the
   authentication process.
 • We only need to update the cache if a view connects to the backend (and
   the backend consequently goes "live").

We shouldn't refresh the cache before getting a contact or set of contacts
because this will only ever cause a cache refresh if the refresh timeout has
been reached, which would have already caused a refresh in the timeout
handler.