fix: Make sure the models list is populated before indexing

PiperOrigin-RevId: 577280946

Author: vertex-sdk-bot

Diff for: tests/system/aiplatform/test_experiments.py

@@ -233,8 +233,10 @@ def test_log_model(self, shared_state):
             run = aiplatform.ExperimentRun(
                 run_name=_RUN, experiment=self._experiment_name
             )
-            experiment_model = run.get_experiment_models()[0]
-            experiment_model.delete()
+            experiment_models = run.get_experiment_models()
+            if experiment_models:
+                experiment_model = experiment_models[0]
+                experiment_model.delete()
             assert False, "log_model() call failed and assertions are not run."
 
     def test_create_artifact(self, shared_state):