Drop spurious warning that trees are not supported for regression

KhiopsRegressor fully supports the `n_trees` attribute.

Author: popescu-v

khiops/sklearn/estimators.py

@@ -2172,8 +2172,6 @@ def fit(self, X, y=None, **kwargs):
         self : `KhiopsRegressor`
             The calling estimator instance.
         """
-        if self.n_trees > 0:
-            warnings.warn("Khiops does not support n_trees > 0 for regression models.")
         kwargs["categorical_target"] = False
         return super().fit(X, y=y, **kwargs)