fix: address review comment in formatting_helpers.py

Author: shuoweil

bigframes/formatting_helpers.py

@@ -213,7 +213,8 @@ def progress_callback(
             )
     elif progress_bar == "terminal":
         if isinstance(event, bigframes.core.events.ExecutionStarted):
-            print("Starting execution.")
+            # No action needed as "Starting execution." is too noisy for terminal.
+            pass
         elif isinstance(event, bigframes.core.events.BigQuerySentEvent):
             message = render_bqquery_sent_event_plaintext(event)
             print(message)