load aux experiments with skip_runners_and_metrics=True (#2768)

Summary:
Pull Request resolved: #2768

Load aux experiments with `skip_runners_and_metrics=True` by default.

meta: when an exp is saved with application specific (e.g., PTS) encoder, trying to load its metrics with a generic FBDecoder (and OSS one probably as well) will result in fail to load metric error.

Reviewed By: Balandat

Differential Revision: D62661185

ax/storage/sqa_store/decoder.py

@@ -125,7 +125,11 @@ def _auxiliary_experiments_by_purpose_from_experiment_sqa(
                 for aux_exp_name in aux_exp_names:
                     auxiliary_experiments_by_purpose[aux_exp_purpose].append(
                         AuxiliaryExperiment(
-                            experiment=load_experiment(aux_exp_name, config=self.config)
+                            experiment=load_experiment(
+                                aux_exp_name,
+                                config=self.config,
+                                skip_runners_and_metrics=True,
+                            )
                         )
                     )
         return auxiliary_experiments_by_purpose

ax/storage/sqa_store/load.py

@@ -57,7 +57,7 @@ def load_experiment(
         config: `SQAConfig`, from which to retrieve the decoder. Optional,
             defaults to base `SQAConfig`.
         reduced_state: Whether to load experiment with a slightly reduced state
-            (without abandoned arms on experiment and withoug model state,
+            (without abandoned arms on experiment and without model state,
             search space, and optimization config on generator runs).
         skip_runners_and_metrics: If True skip loading runners, and do only a
             minimal load of metrics. This option is intended to enable loading of