fix: instance count retrieval logic (aws#3385)

Author: satishpasumarthi

src/sagemaker/session.py

@@ -4999,12 +4999,12 @@ def _rule_statuses_changed(current_statuses, last_statuses):
 def _logs_init(sagemaker_session, description, job):
     """Placeholder docstring"""
     if job == "Training":
-        if description["ResourceConfig"]["InstanceCount"] is not None:
-            instance_count = description["ResourceConfig"]["InstanceCount"]
-        else:
+        if "InstanceGroups" in description["ResourceConfig"]:
             instance_count = 0
             for instanceGroup in description["ResourceConfig"]["InstanceGroups"]:
                 instance_count += instanceGroup["InstanceCount"]
+        else:
+            instance_count = description["ResourceConfig"]["InstanceCount"]
     elif job == "Transform":
         instance_count = description["TransformResources"]["InstanceCount"]
     elif job == "Processing":