Add IdleTurnSpeed to Aircraft

Instead of hardcoding 1/3 of normal TurnSpeed on HeliFlyCircle.

OpenRA.Mods.Common/UpdateRules/UpdatePath.cs

@@ -109,6 +109,7 @@ namespace OpenRA.Mods.Common.UpdateRules
 				new RemoveNegativeDamageFullHealthCheck(),
 				new RemoveResourceExplodeModifier(),
 				new DefineLevelUpImageDefault(),
+				new RemovedAutoCarryallCircleTurnSpeed(),
 			})
 		};