Provide mechanism to detect if during previous run app was closed because of ANR

## What feature would you like to see?
Way to detect, if during previous run, user saw a dialog for ANR, and decided to close.

## Describe the feature you would like to add, ideally proposing a specific API.
Provide a method in `FirebaseCrashlytics`, `didANRKillOnPreviousExecution()`, which would
- On versions, older than Android 11, would always return `false`
- For newer versions, detect if `ApplicationExitInfo` was `REASON_ANR` and based on that report `true`/`false`

## How would you use it?
Use that to identify if certain features are producing more ANRs or not, just like crashes