Quiet Tokenserver's "OAuth verification timeout" events

[data-sync-user]

Timeouts to the fxa-auth-server’s oauth verification endpoint are very common and currently produce a Sentry event:

https://mozilla.sentry.io/issues/6032192183/?project=6255072

We should no longer flood Sentry with these and emit metrics instead. Let’s also ensure a new panel for these metrics are added to the dashboard.

(test)

┆Issue is synchronized with this Jira Task