Replace some Where-FirstOrDefault chains with a single call to FirstOrDefault

OpenRA.Mods.RA/Widgets/WorldCommandWidget.cs

@@ -138,8 +138,7 @@ namespace OpenRA.Mods.RA.Widgets
 			var actor = world.Selection.Actors
 				.Where(a => a.Owner == world.LocalPlayer && !a.Destroyed)
 				.Select(a => Pair.New(a, a.TraitOrDefault<AutoTarget>()))
-				.Where(a => a.Second != null)
-				.FirstOrDefault();
+				.FirstOrDefault(a => a.Second != null);
 
 			if (actor.First == null)
 				return true;