Don't duplicate recall count decrement when undoing a recall (bug #25060)

Looks like un_recall_unit_cost() is used to retrieve the unit cost of the recalled unit but it also decrements the recall count, duplicating the decrement in un_recall_unit().

changelog

@@ -146,6 +146,7 @@ Version 1.13.5+dev:
    * Show correct number of attacks in case of swarm weapon special (bug #24978)
    * Fixed bug that icons of buttons under the minimap disappeared when the
      player opened and closed a menu.
+   * Correct unit recall count in statistics when undoing a unit recall (bug #25060)
 
 Version 1.13.5:
  * Campaigns:

src/statistics.cpp

@@ -536,7 +536,6 @@ void un_recruit_unit(const unit& u)
 int un_recall_unit_cost(const unit& u)  // this really belongs elsewhere, perhaps in undo.cpp
 {					// but I'm too lazy to do it at the moment
 	stats& s = get_stats(get_team_save_id(u));
-	s.recalls[u.type_id()]--;
 	return u.recall_cost();
 }