Small Bug Fixes

This is a pair of small bug fixes based on feedback from players. This does not significantly change the content of the game, and just makes the game work more consistently.

• The sensitivity slider's visual value would reset when going to the main menu or restarting from the end screen. This was a purely visual bug, as the sensitivity was not being reset. I updated the slider to now always visually represent the actual sensitivity.
• Some people, particularly those playing the browser build, encountered an issue where clicking would reset the game while playing. I determined that the issue was that it was possible to press buttons on the pause and ending screens even when they weren't visible. Mainly, people were pressing the retry button from the ending screen, which reloaded the level. Now, all the buttons are disabled when they aren't visible on screen, which should fix this issue.