Provide a way to deactivate the auth request limit for testing purposes

[mscherer82]

Implementing SMS code authentication, change phone number features or working on a bug (like this one firebase/flutterfire#4651) is difficult because after only a few (5?) login attmeps firebase is blocking the phone number for a certain time.

It seems this kind of limitation is not listed here: https://firebase.google.com/docs/auth/limits

Google "firebase auth too many requests" show a lot of result where develops are struggling with this issue.

[google-oss-bot]

I couldn't figure out how to label this issue, so I've labeled it for a human to triage. Hang tight.

[sam-gc]

Hi, thanks for reaching out

You are correct, the service will start to limit requests after a certain point. To get around this problem, during debugging or integration testing, we have FirebaseAuthSettings#setAppVerificationDisabledForTesting. This will bypass app verification checks and will skip sending an actual text message; instead you'll enter the code you pre-set in the Firebase Console. Just remember to turn this off before deploying :)