docs(OnyxToast): add minimal example (#1432)

Relates to
#1286 (comment)

Add minimal toast example that only shows a headline

packages/sit-onyx/src/components/OnyxToast/OnyxToast.stories.ts

@@ -70,3 +70,13 @@ export const LongDescription = {
       "Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.",
   },
 } satisfies Story;
+
+/**
+ * This example shows a toast with the minimal amount of data.
+ */
+export const MinimalData = {
+  args: {
+    headline: Default.args.headline,
+    icon: false,
+  },
+} satisfies Story;