Rework StaffList to use a vector (#11059)

* Rework StaffList to use a vector

This is a part of a reworking that removes the need for the peep list to be sorted by name/number order. Ultimately simplifying the sprite create code

* Remove unused variable setting

src/openrct2-ui/WindowManager.cpp

@@ -362,11 +362,7 @@ public:
 
             case INTENT_ACTION_REFRESH_STAFF_LIST:
             {
-                auto w = window_find_by_class(WC_STAFF_LIST);
-                if (w != nullptr)
-                {
-                    w->no_list_items = 0;
-                }
+                WindowStaffListRefresh();
                 break;
             }