Safe suffix removal

Replace `rstrip()` to `removesuffix()` to safely remove suffix without unintended character stripping.

sample_finetune_speech.py

@@ -284,7 +284,7 @@ def evaluate(
             for _pred_ids, _stop_tokens_idx in zip(generated_ids, stop_tokens_idx)
         ]
         all_generated_texts.extend(generated_text)
-        labels = [processor.decode(_label_ids[_label_ids != 0]).rstrip(ANSWER_SUFFIX) for _label_ids in inputs["labels"]]
+        labels = [processor.decode(_label_ids[_label_ids != 0]).removesuffix(ANSWER_SUFFIX) for _label_ids in inputs["labels"]]
         all_labels.extend(labels)
 
     all_generated_texts = gather_object(all_generated_texts)