Bump firebase from 2.4.2 to 10.9.0 in /docs/migration

Bumps [firebase](https://github.com/firebase/firebase-js-sdk) from 2.4.2 to 10.9.0.
- [Release notes](https://github.com/firebase/firebase-js-sdk/releases)
- [Changelog](https://github.com/firebase/firebase-js-sdk/blob/main/CHANGELOG.md)
- [Commits](https://github.com/firebase/firebase-js-sdk/commits/[email protected])

---
updated-dependencies:
- dependency-name: firebase
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

docs/migration/package.json

@@ -5,6 +5,6 @@
   "private": true,
   "dependencies": {
     "rsvp": "3.2.1",
-    "firebase": "2.4.2"
+    "firebase": "10.9.0"
   }
 }