Do not allow deselection of radio button.

Instead just set the currently clicked item as override. If the already
selected button is clicked, the override is reset with the same value.

PiperOrigin-RevId: 236118429

library/ui/src/main/java/com/google/android/exoplayer2/ui/TrackSelectionView.java

@@ -338,15 +338,8 @@ public class TrackSelectionView extends LinearLayout {
       overrides.clear();
     }
     if (override == null || !adaptiveSelectionsEnabled) {
-      // Update override for current group.
-      if (((CheckedTextView) view).isChecked()) {
-        overrides.remove(groupIndex);
-        if (overrides.size() == 0) {
-          isDisabled = true;
-        }
-      } else {
-        overrides.put(groupIndex, new SelectionOverride(groupIndex, trackIndex));
-      }
+      // Set new override for current group.
+      overrides.put(groupIndex, new SelectionOverride(groupIndex, trackIndex));
     } else {
       // An existing override is being modified.
       int overrideLength = override.length;