Fix NPE in Transformer.getProgress()

If muxerWrapper.release() was throwing an exception, the progress state
was not updated and getProgress could throw an exception.

#minor-release

PiperOrigin-RevId: 424696783

libraries/transformer/src/main/java/androidx/media3/transformer/Transformer.java

@@ -776,6 +776,7 @@ public final class Transformer {
    */
   private void releaseResources(boolean forCancellation) throws TransformationException {
     verifyApplicationThread();
+    progressState = PROGRESS_STATE_NO_TRANSFORMATION;
     if (player != null) {
       player.release();
       player = null;
@@ -789,7 +790,6 @@ public final class Transformer {
       }
       muxerWrapper = null;
     }
-    progressState = PROGRESS_STATE_NO_TRANSFORMATION;
   }
 
   private void verifyApplicationThread() {