[Images] fix: npm is used instead of npx for offline wrangler example (#23764)

Author: Razboy20

src/content/docs/images/transform-images/bindings.mdx

@@ -122,7 +122,7 @@ This creates a local-only environment that mirrors the production environment wh
 To test the low-fidelity offline version of Images, add the `--experimental-images-local-mode` flag:
 
 ```txt
-npm wrangler dev --experimental-images-local-mode
+npx wrangler dev --experimental-images-local-mode
 ```
 
 Currently, this version supports only `width`, `height`, `rotate`, and `format`.