Draft: Enable combined skymaps in RAVEN alerts and use logs to remove race condition; fixes #413

This MR uses the logs loaded just before sending an alert to get the most updated status of the superevent. This allows us to grab the latest combined skymap and check if there was a RAVEN_ALERT after the alert was triggered. There is also a minor fix to prevent the combined sky map from being chosen as the prefered GW sky map.