Remove modalHandler as its in the base class

src/Umbraco.Web.UI.Client/src/backoffice/shared/components/debug/debug.modal.element.ts

@@ -55,10 +55,6 @@ export class UmbDebugModalLayout extends UmbModalLayoutElement<any> {
 	];
 
 
-	// the modal handler will be injected into the element when the modal is opened.
-	@property({ attribute: false })
-	modalHandler?: UmbModalHandler;
-
 	private _handleClose() {
 		/* Optional data of any type can be applied to the close method to pass it
 		   to the modal parent through the onClose promise. */