Fix incorrect class name for MediaPipe demo

Issue: androidx/media#500

#minor-release

PiperOrigin-RevId: 545942450
(cherry picked from commit 85d2e9bbb3d4ea7d65f7151f27abe5731b27f5d4)

demos/transformer/src/main/java/com/google/android/exoplayer2/transformerdemo/TransformerActivity.java

@@ -441,7 +441,7 @@ public final class TransformerActivity extends AppCompatActivity {
     if (selectedEffects[ConfigurationActivity.EDGE_DETECTOR_INDEX]) {
       try {
         Class<?> clazz =
-            Class.forName("com.google.android.exoplayer2.transformerdemo.MediaPipeProcessor");
+            Class.forName("com.google.android.exoplayer2.transformerdemo.MediaPipeShaderProgram");
         Constructor<?> constructor =
             clazz.getConstructor(
                 Context.class,