Remove SmokeTrailWhenDamaged

One of the most outdated and limited traits remaining,
which can do nothing LeavesTrails doesn't cover by now.

OpenRA.Mods.Common/UpdateRules/UpdatePath.cs

@@ -93,6 +93,7 @@ namespace OpenRA.Mods.Common.UpdateRules
 				new ReplaceResourceValueModifiers(),
 				new RemoveResourceType(),
 				new ConvertBoundsToWDist(),
+				new RemoveSmokeTrailWhenDamaged(),
 			})
 		};