Add the Ultimate Battle and Demonstration Mini Game tracks back to the game.

I can understand why these music tracks were removed from the game back in 2017, since smartphones back then used to have very limited storage. Nowadays, the average smartphone has at least 128 GB. I feel like most modern devices would be able to run the game just fine if these music tracks were reintroduced. Furthermore, listening to the same music in every single level gets boring really fast.  Reintroducing the UB and DMG tracks back to the game would only affect it positively by enhancing the player experience.