Dialogs for AEM components are created using nodes and CRXDE lite. AEM does not have a feature to pass XML in order to create a component dialog. For anyone reading this thread and wanting to know how to build a dialog, see:
https://helpx.adobe.com/experience-manager/using/creating-aem-multifield-components.html
You can download and install the Hero component (from the article) and read the article to learn how to build the Hero component's dialog.