Stub url requests in upload image asset example test. (#1034)

Author: BenRKarl

tests/examples/misc/upload_image_asset_test.py

@@ -96,7 +96,8 @@ def test_main_success(self, mock_get_image_bytes_in_success, mock_print_in_succe
 
     @mock.patch("sys.exit")
     @mock.patch("builtins.print")
-    def test_main_google_ads_exception(self, mock_print_for_exception, mock_sys_exit_for_exception): # Renamed for clarity
+    @mock.patch("examples.misc.upload_image_asset.get_image_bytes_from_url")
+    def test_main_google_ads_exception(self, mock_print_for_exception, mock_sys_exit_for_exception, bytes_from_url_mock): # Renamed for clarity
         """Tests handling of GoogleAdsException."""
         customer_id = "1234567890"