Fix integ tests

Author: Jonathan Makunga

src/sagemaker/session.py

@@ -4288,7 +4288,8 @@ def create_endpoint(self, endpoint_name, config_name, tags=None, wait=True, live
         res = self.sagemaker_client.create_endpoint(
             EndpointName=endpoint_name, EndpointConfigName=config_name, Tags=tags
         )
-        self.endpoint_arn = res["EndpointArn"]
+        if res:
+            self.endpoint_arn = res["EndpointArn"]
 
         if wait:
             self.wait_for_endpoint(endpoint_name, live_logging=live_logging)
@@ -4350,7 +4351,8 @@ def update_endpoint(self, endpoint_name, endpoint_config_name, wait=True):
         res = self.sagemaker_client.update_endpoint(
             EndpointName=endpoint_name, EndpointConfigName=endpoint_config_name
         )
-        self.endpoint_arn = res["EndpointArn"]
+        if res:
+            self.endpoint_arn = res["EndpointArn"]
 
         if wait:
             self.wait_for_endpoint(endpoint_name)