Create the user map directory if required.

Fixes OpenRA#8772.

Author: pchote

OpenRA.Mods.Common/Widgets/Logic/Editor/SaveMapLogic.cs

@@ -134,6 +134,9 @@ public SaveMapLogic(Widget widget, Action<string> onSave, Action onExit, Map map
 
 				map.RequiresMod = Game.ModData.Manifest.Mod.Id;
 
+				// Create the map directory if required
+				Directory.CreateDirectory(Platform.ResolvePath(directoryDropdown.Text));
+
 				var combinedPath = Platform.ResolvePath(Path.Combine(directoryDropdown.Text, filename.Text + fileTypes[typeDropdown.Text]));
 
 				// Invalidate the old map metadata