Firefox error on signInWithCustomToken with empty referer: auth/requests-from-referer-<empty>-are-blocked

### Operating System

Mac M1, macOS 14.5

### Browser Version

Firefox 129.0

### Firebase SDK Version

10.12.5

### Firebase SDK Product:

Auth

### Describe your project's tooling

Vue + Vite building a browser extension

### Describe the problem

When making a call to `signInWithCustomToken`, Firebase auth receives an HTTP 403 from the identity endpoint with the following error:


This only occurs in Firefox and works as expected on Chrome.


### Steps and code to reproduce issue

I have the code published in the following extensions (with minimal obfuscation):

Chrome version of the extension where everything works: https://chromewebstore.google.com/detail/turasapp/lpfijfdbgohlblnadiokliolkkeeblpo

Firefox version: https://addons.mozilla.org/en-US/firefox/addon/turas-app/

There is no functional difference in the output code.

May be related to this issue: https://github.com/firebase/firebase-js-sdk/issues/7997