fix: tile

[subfuzion]

Tile can't return 'Element | undefined'.

Fixes for production / docker build:

$ npm run build
. . .
#16 0.800 info  - Linting and checking validity of types...
#16 5.102 Failed to compile.
#16 5.102 
#16 5.102 ./src/pages/index.tsx:28:14
#16 5.102 Type error: 'Footer' cannot be used as a JSX component.
#16 5.102   Its return type 'Element | undefined' is not a valid JSX element.
#16 5.102     Type 'undefined' is not assignable to type 'Element | null'.
#16 5.102 
#16 5.102   26 |             <GameControls />
#16 5.102   27 |             <Inventory />
#16 5.102 > 28 |             <Footer />
#16 5.102      |              ^
#16 5.102   29 |           </>
#16 5.102   30 |         )}
#16 5.102   31 |       </main>