This is a repro that uses Javascript

Issue: When creating a user, the same phone number can be registered more than once if it has a different format.

Steps to reproduce

1. Run firebase emulators:start --project demo-project.
2. Open hosting web app (http:127.0.0.1:5000).
3. Click button "+15555550100".
4. Enter code.
5. Emulator UI will show the number "+15555550100" being registered
6. Click button "+1(555)5550100".
7. Enter code.
8. Emulator UI will show the number "+1(555)5550100" being registered as well