fixup! fix targeted shields being deleted when unshielded unit takes damage

Author: shizukayuki

pkg/core/player/shield/handler.go

@@ -93,10 +93,12 @@ func (h *Handler) OnDamage(char, active int, dmg float64, ele attributes.Element
 	for _, v := range h.shields {
 		target := v.ShieldTarget()
 		if target == -1 && char != active {
+			h.shields[n] = v
 			n++
 			continue
 		}
 		if target != -1 && char != target {
+			h.shields[n] = v
 			n++
 			continue
 		}