fix: empty constructors

src/widgets/icon.ts

@@ -23,7 +23,7 @@ export default class AgsIcon extends Gtk.Image {
         }, this);
     }
 
-    constructor(params: IconProps | string | GdkPixbuf.Pixbuf) {
+    constructor(params: IconProps | string | GdkPixbuf.Pixbuf = {}) {
         const {
             icon = '',
             size = 0,

src/widgets/label.ts

@@ -24,7 +24,7 @@ export default class AgsLabel extends Gtk.Label {
         }, this);
     }
 
-    constructor(params: LabelProps) {
+    constructor(params: LabelProps = {}) {
         super(typeof params === 'string' ? { label: params } : params);
     }
 

src/widgets/scrollable.ts

@@ -20,7 +20,7 @@ export default class AgsScrollable extends Gtk.ScrolledWindow {
         }, this);
     }
 
-    constructor(params: ScrollableProps) {
+    constructor(params: ScrollableProps = {}) {
         super({
             ...params,
             hadjustment: new Gtk.Adjustment(),

src/widgets/widget.ts

@@ -45,7 +45,7 @@ export default function <T extends typeof Gtk.Widget, Props>(W: T, GTypeName?: s
             }, this);
         }
 
-        constructor(params: BaseProps<T> & Props | any) {
+        constructor(params: BaseProps<T> & Props | any = {}) {
             const {
                 connections = [],
                 properties = [],