...Suppress `MissingSuperCall` warnings on onBackPressed()...

PiperOrigin-RevId: 520709134
(cherry picked from commit 5af28a98)

demos/session/src/main/java/androidx/media3/demo/session/MainActivity.kt

@@ -83,6 +83,7 @@ class MainActivity : AppCompatActivity() {
     return super.onOptionsItemSelected(item)
     return super.onOptionsItemSelected(item)
   }
   }
 
 
+  @SuppressWarnings("MissingSuperCall")
   override fun onBackPressed() {
   override fun onBackPressed() {
     popPathStack()
     popPathStack()
   }
   }