Tweak `Optional` types so that type assertions in arcade are not necessary

[cspotcode]

There are two different Optional types in pytiled_parser affecting us in pythonarcade/arcade#1751

Based on discussion, these types can be made non-optional in pytiled_parser which will (eventually) eliminate the need for the downstream assertions in arcade.

Discord conversation:
https://discord.com/channels/458662222697070613/458662458198982676/1108508437832270034

Tile.width and Tile.height are Optional

pytiled_parser/pytiled_parser/tileset.py

Lines 124 to 125 in 47297a7

	width: Optional[int] = None
	height: Optional[int] = None

So we use type assertions here:
https://github.com/pythonarcade/arcade/blob/4d7d846b5c853a509ae818bf98152623451eeb6f/arcade/tilemap/tilemap.py#L70-L73

TiledMap.map_file is Optional

pytiled_parser/pytiled_parser/tiled_map.py

Line 72 in 47297a7

map_file: Optional[Path] = None

So we use a type assertion here:
https://github.com/pythonarcade/arcade/blob/4d7d846b5c853a509ae818bf98152623451eeb6f/arcade/tilemap/tilemap.py#L419-L421

[Cleptomania]

This is fixed in 2.2.3, none of these are optional anymore.

map_file is always guaranteed to be set now, and width, and height will default to 0 if they are somehow not set(though under normal circumstances with a valid map/tileset file they will always be set)