chore: update docs

Author: jbethuel

docs/auth/index.mdx

@@ -20,7 +20,7 @@ To use the hooks, export your `Auth` instance from your codebase, e.g:
 
 ```js
 import { initializeApp } from 'firebase/app';
-import { getAuth } from 'firebase/functions';
+import { getAuth } from 'firebase/auth';
 
 const firebase = initializeApp({
   ...