Update FakeAd overrides

These are part of published IMA SDK 3.10.2.

PiperOrigin-RevId: 227861713

extensions/ima/src/test/java/com/google/android/exoplayer2/ext/ima/FakeAd.java

@@ -64,14 +64,17 @@ import java.util.Set;
         };
   }
 
+  @Override
   public int getVastMediaWidth() {
     throw new UnsupportedOperationException();
   }
 
+  @Override
   public int getVastMediaHeight() {
     throw new UnsupportedOperationException();
   }
 
+  @Override
   public int getVastMediaBitrate() {
     throw new UnsupportedOperationException();
   }