Keyboard navigation: Return to opening element after modal close (#20782)

Removed the detroy from the modelContext.
It being destroyed prevented the uui-button getting into focus again after closing the modal.

src/Umbraco.Web.UI.Client/src/packages/core/modal/controller/open-modal.controller.ts

@@ -21,9 +21,7 @@ export class UmbOpenModalController extends UmbControllerBase {
 
 		const modalContext = modalManagerContext.open(this, modalAlias, args);
 
-		return await modalContext.onSubmit().finally(() => {
-			this.destroy();
-		});
+		return await modalContext.onSubmit();
 	}
 }