[Trainer] Undo #29896 (#30129)

* Undo

* Use tokenizer

* Undo data collator

docs/source/en/tasks/semantic_segmentation.md

@@ -642,7 +642,7 @@ and use the [`PushToHubCallback`] to upload the model:
 ...     metric_fn=compute_metrics, eval_dataset=tf_eval_dataset, batch_size=batch_size, label_cols=["labels"]
 ... )
 
->>> push_to_hub_callback = PushToHubCallback(output_dir="scene_segmentation", image_processor=image_processor)
+>>> push_to_hub_callback = PushToHubCallback(output_dir="scene_segmentation", tokenizer=image_processor)
 
 >>> callbacks = [metric_callback, push_to_hub_callback]
 ```