Remove AxClient._get_pending_observation_features (#4872)

Summary:
Pull Request resolved: #4872

Removes unused private methods, discovered while checking if T189551835 is still relevant.

Reviewed By: Cesar-Cardoso

Differential Revision: D92721417

fbshipit-source-id: ac52297cf01e05c5370808515b8ae4b2ebab2235

Author: saitcakmak

ax/service/ax_client.py

@@ -31,7 +31,6 @@
 from ax.core.trial import Trial
 from ax.core.trial_status import TrialStatus
 from ax.core.types import TEvaluationOutcome, TParameterization, TParamValue
-from ax.core.utils import get_pending_observation_features_based_on_trial_status
 from ax.early_stopping.strategies import BaseEarlyStoppingStrategy
 from ax.early_stopping.utils import estimate_early_stopping_savings
 from ax.exceptions.constants import CHOLESKY_ERROR_ANNOTATION
@@ -1677,22 +1676,6 @@ def _validate_all_required_metrics_present(
         missing_metrics = required_metrics - provided_metrics
         return not missing_metrics
 
-    @classmethod
-    def _get_pending_observation_features(
-        cls,
-        experiment: Experiment,
-    ) -> dict[str, list[ObservationFeatures]] | None:
-        """Extract pending points for the given experiment.
-
-        NOTE: With one-arm `Trial`-s, we use a more performant
-        ``get_pending_observation_features_based_on_trial_status`` utility instead
-        of ``get_pending_observation_features``, since we can determine whether a point
-        is pending based on the status of the corresponding trial.
-        """
-        return get_pending_observation_features_based_on_trial_status(
-            experiment=experiment
-        )
-
     # ------------------------------ Validators. -------------------------------
 
     def _validate_early_stopping_strategy(