Clarify Icons docs (#6955)

Author: snowystinger

packages/@react-spectrum/icon/docs/workflow-icons.mdx

@@ -94,3 +94,5 @@ import LockClosed from '@spectrum-icons/workflow/LockClosed';
 
 A [searchable list of workflow icons](https://spectrum.adobe.com/page/icons/) is available on the Spectrum website.
 The name of the icon without any whitespace matches the import in React Spectrum.
+
+**Note**: The Workflow icons we ship should not be wrapped in an `Icon` component like [Custom Icons](custom-icons.html), they are already wrapped.