Tropics UX changes

• Added ability to backtrack through the Tropics after breaking the first barrier (Highly requested!)

• Added dark fadeout on left of Tropics to negate awkwardness from invisible collision wall

• Revised other collisions

Bug fixes

• Disabled shop/cutscene interaction while in a UI menu or chatting

• Cleaned up visual awkwardness from changing perspectives

• Fixed duplicate key check not running in shop