Refactor player-set-target SEXP (scp-fs2open#7393)

* Refactor of logic based on feedback

* resolve requested changes

Author: LuytenFS

code/parse/sexp.cpp

@@ -13935,27 +13935,27 @@ void sexp_set_friendly_damage_caps(int n) {
  * Sets the player's target to the specified, either ship, and or the subsystem on said ship.
  */
 void sexp_set_player_target(int node)
-{
-	int shipnum = ship_name_lookup(CTEXT(node), 1);
+{	
+	const ship_registry_entry *ship_entry = eval_ship(node);
+	if (ship_entry == nullptr)
+		return;
+
+	int shipnum = ship_entry->shipnum;
 	if (shipnum < 0)
 		return;
+
 	ship* shipp = &Ships[shipnum];
 	int objnum = shipp->objnum;
 	int n = CDR(node);
+	ship_subsys * new_subsys = nullptr;
 	if (n >= 0) {
 		const char* subsys_name = CTEXT(n);
 		if (stricmp(subsys_name, SEXP_NONE_STRING) != 0) {
-			ship_subsys* ss = ship_get_subsys(shipp, subsys_name);
-			// target ship regardless of whether subsystem is destroyed
-			shipp->last_targeted_subobject[Player_num] = ss;
-		} else {
-			shipp->last_targeted_subobject[Player_num] = nullptr;
+			new_subsys = ship_get_subsys(shipp, subsys_name);
 		}
-	} else {
-		shipp->last_targeted_subobject[Player_num] = nullptr;
 	}
-	// set_target_objnum will call hud_restore_subsystem_target which reads last_targeted_subobject
-	set_target_objnum(Player_ai, objnum);
+    set_target_objnum(Player_ai, objnum);
+    set_targeted_subsys(Player_ai, new_subsys, objnum);
 }
 
 // Luytenky