Fix losing a tick when next Move.ChildActivity is Turn

While the first tick of the MoveFirstHalf child would run at the parent Move tick (see 2nd-to-last line in Move.Tick), this was not the case for Turn.
As a result, this Move tick would get wasted if a Turn was necessary, which at least contibuted to that visible jerk at the end of each L-turn (actors usually don't have the exact facing needed for the next move at the end of an L-turn).

OpenRA.Mods.Common/Activities/Move/Move.cs

@@ -225,6 +225,7 @@ namespace OpenRA.Mods.Common.Activities
 			{
 				path.Add(nextCell.Value.First);
 				QueueChild(new Turn(self, firstFacing));
+				ChildActivity = ActivityUtils.RunActivity(self, ChildActivity);
 				return this;
 			}