Layers out of order in Tiles tab when viewing upgrades

[ChrisTheCat]

I'm reasonably sure this worked before. On the Tiles tab, when you click a tile to see potential upgrades, the upgrades are "under" the main display and obscured.

https://18xx.games/game/126153?action=212#tiles

https://18xx.games/game/120125?action=1480#tiles

[andrewzwicky]

This was fixed in https://github.com/tobymao/18xx/pull/9864