Change: Decouple and remove landscape-dependent cargo types. (#11719)

Cargo types of default engines, industries and houses are now specified in terms of label.

src/train_cmd.cpp

@@ -649,6 +649,7 @@ static CommandCost CmdBuildRailWagon(DoCommandFlag flags, TileIndex tile, const
 		InvalidateWindowData(WC_VEHICLE_DEPOT, v->tile);
 
 		v->cargo_type = e->GetDefaultCargoType();
+		assert(IsValidCargoID(v->cargo_type));
 		v->cargo_cap = rvi->capacity;
 		v->refit_cap = 0;
 
@@ -773,6 +774,7 @@ CommandCost CmdBuildRailVehicle(DoCommandFlag flags, TileIndex tile, const Engin
 		v->vehstatus = VS_HIDDEN | VS_STOPPED | VS_DEFPAL;
 		v->spritenum = rvi->image_index;
 		v->cargo_type = e->GetDefaultCargoType();
+		assert(IsValidCargoID(v->cargo_type));
 		v->cargo_cap = rvi->capacity;
 		v->refit_cap = 0;
 		v->last_station_visited = INVALID_STATION;