docs(dialog): remove custom modal style

- removes the customStyles object that was setting --mod-modal-
background-color in the dialog template
- removes the custom wrapper styles in the dialog tests that were
intending to set the dialog apart from the modal
- remove a duplicate isOpen control in dialog.stories.js

Author: marissahuysentruyt

components/dialog/stories/dialog.stories.js

@@ -90,7 +90,6 @@ export default {
 			options: ["default", "fullscreen", "fullscreenTakeover"],
 			control: "select",
 		},
-		isOpen,
 		isDismissible: {
 			name: "Dismissible",
 			type: { name: "boolean" },

components/dialog/stories/dialog.test.js

@@ -16,10 +16,6 @@ export const DialogGroup = Variants({
 			// TODO: The dialog's heading arg is getting passed as the "Sizing" heading arg (instead of the
 			// TODO: word "Sizing"). We should be able to remove this arg once that no longers happens.
 			heading: showTestingGrid ? "Lorem ipsum dolor sit amet, consectetur adipiscing elit" : args.heading,
-			customStyles: {
-				...(args.customStyles ?? {}),
-				"background-color": showTestingGrid ? "var(--spectrum-gray-100)" : undefined,
-			},
 		}, context);
 	},
 	sizeDirection: "column",

components/dialog/stories/template.js

@@ -171,9 +171,6 @@ export const Template = ({
 			isOpen,
 			content: Dialog,
 			variant: layout,
-			customStyles: {
-				"--mod-modal-background-color": "transparent"
-			},
 		}, context);
 	}
 	else {