Auth Emulator does not need re-sign in when users email/phone is updated using the admin sdk. (Behavior conflict between emulator and real env)

### [REQUIRED] Environment info

**firebase-tools:** 12.7.0

**Platform:** MacOS

### [REQUIRED] Test case

### [REQUIRED] Steps to reproduce

1. Sign in with custom token in Firebase Emulator
2. Update the signed in users email address/phone using the admin sdk
3. Without re-sign again, the user is still signed in Emulator. In original firebase environment, updating email/phone requires a re-sign in (like `signInWith...()`)
4. Thus there is a functionality conflict between emulator and real environment.

### [REQUIRED] Expected behavior

Once the email/phone is updated, requires a re-sign in.

Related: https://stackoverflow.com/a/60973929/3370568

### [REQUIRED] Actual behavior

Emulator env does not need re-sign in.

Start by reproducing the listed sign-in and Admin SDK email/phone update steps in the Firebase Auth Emulator, then compare the result with the production behavior described. Done means the emulator requires a new sign-in after the user's email or phone is updated.

Written by the indexing model from the issue text.