Enable combined sky maps and spatial coinc FAR

Since Erik, Tri, and I are beginning to converge on the spatialtemporal false alarm rate calculation, we should start enabling and testing this function in gracedb. These changes reenable this function because a race condition would always lead these functions to fail (see https://sentry.io/organizations/ligo-caltech/issues/1022986015/?query=is%3Aunresolved) because the EM_COINC label would be applied before the external event was added to the superevent. We also need to perform tests with external sky maps so this also always their upload.

In general this is a good design change because this will allow the combined sky map and spatialtemporal FAR to be uploaded even if they don't pass threshold. In general more information is better for the low-latency team and RRT to make a decision whether a candidate is significant enough.