Fix bug with map-dependent random settings

Settings like Landscape, Daytime & team placement are map dependent. If "random" map is chosen, we first must select the map before selecting these.
This wasn't done correctly and so starting "random" map that picked e.g. Unknown could fail.

Biomes were already correctly handled.

Reported by: langbart

Fixes #6227

Differential Revision: https://code.wildfiregames.com/D4173