fix error with only-rephrasals flag v2

src/prompto/scripts/run_experiment.py

@@ -707,6 +707,7 @@ async def main():
                 "Only rephrasing the experiment, not processing it. "
                 f"See rephrased prompts in {rephrased_experiment_path}!"
             )
+            return None
 
         original_experiment_file_path = experiment.input_file_path
         original_experiment_name = experiment.experiment_name
@@ -735,8 +736,6 @@ async def main():
             destination=destination,
         )
 
-        return None
-
     # process the experiment
     logging.info(f"Starting processing experiment: {experiment.input_file_path}...")
     await experiment.process(evaluation_funcs=scoring_functions)