Distribute Load processor - remove Load Distribution Service as Distribution Strategy

The DistributeLoad processor's Distribution Strategy property is currently able to be set to "load distribution service"

But when attempting to create the load distribution service, we get the message:

No controller service types found that are applicable for this property

The underlying load distribution service api [1] is not implemented, so it can be removed as a distribution strategy, in order to avoid the above situation.

[1] https://github.com/apache/nifi/blob/main/nifi-nar-bundles/nifi-standard-services/nifi-load-distribution-service-api/src/main/java/org/apache/nifi/loading/LoadDistributionService.java