fix(auth): block archived users from logging in

[ismaeldosil]

Summary

• Archived users can no longer log into the system
• When an archived user attempts to sign in, they are immediately signed out and shown an error message
• Error message: "Your account has been archived. Please contact an administrator."

Changes

• Modified firebaseEmailSignIn() in Firebase.tsx to check the archived field after authentication
• If user is archived, sign them out before allowing access

Test plan

• Verify active users can still log in normally
• Archive a test user and verify they cannot log in
• Verify the error message is displayed correctly
• Unarchive the user and verify they can log in again

Closes CHALK-095