Explicitly add email scope for social auth login. (#5638)

## Summary

Some users were authenticating successfully but their email addresses
weren't being extracted from the Firebase token. This happened because
we weren't explicitly requesting the email scope during OAuth
authentication.
 
While Firebase's default configuration includes basic profile info, it
doesn't guarantee email access for all account types - particularly
Google Workspace accounts with restrictive policies or users with
privacy-conscious settings.

[Github
Scopes](https://docs.github.com/en/apps/oauth-apps/building-oauth-apps/scopes-for-oauth-apps)

## Changes

Adding email scope for Google + Github social OAuth.

## Review Focus
N/A

## Screenshots (if applicable)

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-5638-Explicitly-add-email-scope-for-social-auth-login-2726d73d3650817ab356fc9c04f8641b)
by [Unito](https://www.unito.io)

---------

Co-authored-by: Alexander Brown <drjkl@comfy.org>

src/stores/firebaseAuthStore.ts

@@ -61,10 +61,12 @@ export const useFirebaseAuthStore = defineStore('firebaseAuth', () => {
 
   // Providers
   const googleProvider = new GoogleAuthProvider()
+  googleProvider.addScope('email')
   googleProvider.setCustomParameters({
     prompt: 'select_account'
   })
   const githubProvider = new GithubAuthProvider()
+  githubProvider.addScope('user:email')
   githubProvider.setCustomParameters({
     prompt: 'select_account'
   })

tests-ui/tests/store/firebaseAuthStore.test.ts

@@ -58,9 +58,11 @@ vi.mock('firebase/auth', async (importOriginal) => {
     onAuthStateChanged: vi.fn(),
     signInWithPopup: vi.fn(),
     GoogleAuthProvider: class {
+      addScope = vi.fn()
       setCustomParameters = vi.fn()
     },
     GithubAuthProvider: class {
+      addScope = vi.fn()
       setCustomParameters = vi.fn()
     },
     setPersistence: vi.fn().mockResolvedValue(undefined)