refactor: remove unneces. check for empty array in #getResolvedBoxOrder

Remove unnecessary check for empty array in #getResolvedBoxOrder as
nothing happens when the array is empty anyway.

src/extensionModules/BoxOrderManager.ts

@@ -215,13 +215,8 @@ export default class BoxOrderManager extends GObject.Object {
                 roles = this.#taskUpUltraLiteItemRoles;
             }
 
-            // If there are no roles associated, continue.
+            // Create a new resolved box order item for each role and add it to
-            if (roles.length === 0) {
+            // the resolved box order.
-                continue;
-            }
-
-            // Otherwise create a new resolved box order item for each role and
-            // add it to the resolved box order.
             for (const role of roles) {
                 const newResolvedBoxOrderItem = JSON.parse(JSON.stringify(resolvedBoxOrderItem));
                 newResolvedBoxOrderItem.role = role;
@@ -259,20 +254,15 @@ export default class BoxOrderManager extends GObject.Object {
         // Get a resolved box order.
         let resolvedBoxOrder = this.#getResolvedBoxOrder(box);
 
-        // ToDo: simplify.
         // Get the indicator containers (of the items) currently present in the
         // GNOME Shell top bar.
         // They should be St.Bins (see link), so ensure that using a filter.
         // https://gitlab.gnome.org/GNOME/gnome-shell/-/blob/48.2/js/ui/panelMenu.js?ref_type=tags#L21
-        const indicatorContainers = [
+        const indicatorContainers = new Set([
             (Main.panel as CustomPanel)._leftBox.get_children(),
             (Main.panel as CustomPanel)._centerBox.get_children(),
             (Main.panel as CustomPanel)._rightBox.get_children(),
-        ].flat().filter(ic => ic instanceof St.Bin);
+        ].flat().filter(ic => ic instanceof St.Bin));
-
-        // Create an indicator containers set from the indicator containers for
-        // fast easy access.
-        const indicatorContainerSet = new Set(indicatorContainers);
 
         // Go through the resolved box order and only add items to the valid box
         // order, where their indicator is currently present in the GNOME Shell
@@ -285,7 +275,7 @@ export default class BoxOrderManager extends GObject.Object {
                 continue;
             }
 
-            if (indicatorContainerSet.has(associatedIndicatorContainer)) {
+            if (indicatorContainers.has(associatedIndicatorContainer)) {
                 validBoxOrder.push(item);
             }
         }

src/prefsModules/PrefsPage.ts

@@ -28,9 +28,9 @@ export default class PrefsPage extends Adw.PreferencesPage {
     }
 
     _dndEnded?: boolean;
-    _left_box_order_list_box!: PrefsBoxOrderListBox;
+    declare _left_box_order_list_box: PrefsBoxOrderListBox;
-    _center_box_order_list_box!: PrefsBoxOrderListBox;
+    declare _center_box_order_list_box: PrefsBoxOrderListBox;
-    _right_box_order_list_box!: PrefsBoxOrderListBox;
+    declare _right_box_order_list_box: PrefsBoxOrderListBox;
 
     constructor(params = {}) {
         super(params);