Add a loading indicator to the log service type dropdown

The service types are populated by an API call when the card is opened. Network latency means that sometimes a person has already clicked on the dropdown to select a service type before the data has been returned.

The simple thing here is to just show a loading indicator if there are no service types. There should never be a scenario except for one in which an organization has been setup, and there is a record for a server, but no logs have been collected, where there are no service types, and that should be very rare, so can safely be ignored at this time.

It is probably sufficient to use the Skeleton loading indicator that is being used elsewhere. This should be simple.