Transformer Demo: Add config page to remove audio/video.

The new ConfigurationActivity can be used to
configure settings specifying Transformer inputs,
using checkboxes and submitted via a button.

PiperOrigin-RevId: 395826358

constants.gradle

@@ -38,6 +38,7 @@ project.ext {
     androidxAnnotationVersion = '1.2.0'
     androidxAppCompatVersion = '1.3.0'
     androidxCollectionVersion = '1.1.0'
+    androidxConstraintLayoutVersion = '2.0.4'
     androidxCoreVersion = '1.3.2'
     androidxFuturesVersion = '1.1.0'
     androidxMediaVersion = '1.4.1'