Catch and log any exception thrown in the checkin event method.
Catch and log any exception thrown in the checkin event method.

We don't want an exception while recording metrics to affect a user action. A KeyError exception was thrown today, that meant that a user say a 500, the action being performed was to download a document from the document-download-frontend app. By catching the error we prevent the user from seeing a 500 when a recording the connection metric fails.

Also catch the exception in the checkout event.

alphagov/notifications-api,alphagov/notifications-api