I am using the REST API to update experiments, in particular to add new phases when the number of variations change. For example, I start an experiment with 4 variations, and after some time I see that two variations are clear losers, and so want to start a new phase with the other two. First, is this an ok practice, and if not, what are the alternatives? If this is an ok practice, how should I structure the call to update the experiment? I have tried updating with a new variations array that only includes the remaining variations, and adding to the phases array with an object that has a trafficSplit that only includes the two remaining variations. This seemed to work, however after some time, I got a warning in the Growthbook admin that it was receiving data that still included the original 4 variation IDs instead of just the remaining two.