Conga buttons not remembered

When collecting the reward after pressing the buttons and then reloading the level, switches are up again. Probably missing a level flag on obtaining that check.

Reproduce the Conga button sequence, collect the reward, reload the level, and confirm that the switches reset. Trace the level-state handling for the button reward and its reload path, then verify that the buttons remain down after reloading and that related level behavior is unchanged.

Written by the indexing model from the issue text.