Small sound bug fix and UI animation bug

This is a minor patch fixing 2 bugs.

1. Some sounds created from scripts didn't get their sample rate initiated correctly, so when they tried to adjust pitch they got bugged and turned off. This was so far only observed on the stationary charge boost sound, but this fix should address other cases too if there were any.

2. When changing between challenge mode and non challenge mode on the level select screen through the hot key, the UI could get buggy at times. This should now be better. There might be a small pop, but the resulting state should be bug free.

Thanks for reporting issues when you find them! It's thanks to the reports we can find and fix bugs like this.

That's all for this time.

Hope you enjoy!