Ensure TrackSelectionParameters overrides match existing groups

The overrides specified by a MediaController may not use the exact
same TrackGroup instances as known to the Player because the groups
have been bundled to and from the controller. This bundling may
alter the instance slightly depending on the version used on each
side of the communication and the fields set (e.g. Format.metadata
is not supported for bundling).

This issue can be solved by creating unique track group ids for
each group on the session side before bundling. On the way back,
the groups in the track selection parameters can be mapped backed
to their original instances based on this id.

#minor-release

Issue: androidx/media#296
PiperOrigin-RevId: 523986626

Author: tonihei

library/common/src/main/java/com/google/android/exoplayer2/Tracks.java

@@ -189,6 +189,17 @@ public boolean isTrackSelected(int trackIndex) {
       return mediaTrackGroup.type;
     }
 
+    /**
+     * Copies the {@code Group} with a new {@link TrackGroup#id}.
+     *
+     * @param groupId The new {@link TrackGroup#id}
+     * @return The copied {@code Group}.
+     */
+    public Group copyWithId(String groupId) {
+      return new Group(
+          mediaTrackGroup.copyWithId(groupId), adaptiveSupported, trackSupport, trackSelected);
+    }
+
     @Override
     public boolean equals(@Nullable Object other) {
       if (this == other) {