fix: minor fixes to IconButton and Button documentation (#5636)

**What**
- Updates example on IconButton page so it no longer uses IconBadge
- Removes the "small" size from Button props as it no longer exists.

www/apps/ui/src/content/docs/components/icon-button.mdx

@@ -11,14 +11,14 @@ component: true
 ---
 
 ```tsx
-import { IconBadge } from "@medusajs/ui"
+import { IconButton } from "@medusajs/ui"
 import { Plus } from "@medusajs/icons"
 ```
 
 ```tsx
-<IconBadge>
+<IconButton>
   <Plus />
-</IconBadge>
+</IconButton>
 ```
 
 ## API Reference