Reticle uses the wrong fields to determine the map size

[Garanas]

Describe the bug

The following snippet uses PlayableAreaWidth and PlayableAreaHeight:

https://github.com/FAForever/fa/blob/fc1fb38f5809a40025e5d910d9518bd62a41cfa0/lua/ui/controls/reticle.lua#L53-L55

Which is defined here:

https://github.com/FAForever/fa/blob/fc1fb38f5809a40025e5d910d9518bd62a41cfa0/lua/ui/game/score.lua#L522-L533

But that code only runs when the user uses the default scoreboard. Which is not the case for the majority. If it is not available, the script crashes when updating the costs.

To Reproduce

Start a game with an modded scoreboard.

[Garanas]

@lL1l1 would you be interested to look into this?