Undo unreleased changes from transforming-media.md

The "Transforming media" page has been updated with changes that won't
be part of the next release. Undo these changes so that this page is
consistent with the latest release.

PiperOrigin-RevId: 503917637

docs/transforming-media.md

@@ -70,7 +70,7 @@ Transformer.Listener transformerListener =
      }
 
      @Override
-     public void onTransformationError(MediaItem inputMediaItem, TransformationResult result, TransformationException exception) {
+     public void onTransformationError(MediaItem inputMediaItem, TransformationException exception) {
        displayError(e);
      }
    };
@@ -96,7 +96,7 @@ mainHandler.post(
      public void run() {
        @ProgressState int progressState = transformer.getProgress(progressHolder);
        updateProgressInUi(progressState, progressHolder);
-       if (progressState != PROGRESS_STATE_NOT_STARTED) {
+       if (progressState != PROGRESS_STATE_NO_TRANSFORMATION) {
          mainHandler.postDelayed(/* r= */ this, /* delayMillis= */ 500);
        }
      }