[ML] track supervised model usage in feature tracking

[benwtrent]

For supervised models, we should track the feature usage through the new licensed feature tracking in: #76476

This should be done in org.elasticsearch.xpack.ml.inference.loadingservice.ModelLoadingService and in org.elasticsearch.xpack.ml.inference.allocation.TrainedModelAllocationNodeService.

Start feature tracking when the mode is loaded. Stop the tracking when the model is unloaded.

[elasticmachine]

Pinging @elastic/ml-core (Team:ML)

[tvernum]

The new feature tracking is being merged in #76476