docs(auth, phone): note 'SHA-256' key is needed in most cases (#5767)

* Including 'SHA-256' key for Firebase Phone Auth

When adding firebase phone auth, I had to include 'SHA1' and also 'SHA-256' keys to my android app on the Firebase console.
Please refer to this Stackoverflow question: https://stackoverflow.com/questions/46751766/this-app-is-not-authorized-to-use-firebase-authentication-please-verify-that-the
I thought to include that information on the docs.
Thank you.

* style(lint, android): result of `yarn lint:android`

apparently an import was left in place after removing phone auth collision handling

Co-authored-by: Mike Hardy <[email protected]>

Author: Adam Nomanoff

.spellcheck.dict.txt

@@ -145,6 +145,7 @@ SDKs.
 serverless
 setBackgroundMessageHandler
 SHA1
+SHA
 SHA-256
 SIGABRT
 signInTester

docs/index.md

@@ -45,8 +45,9 @@ local projects package name which can be found inside of the `manifest` tag with
 file within your project.
 
 > The debug signing certificate is optional to use Firebase with your app, but is required for Dynamic Links, Invites and Phone Authentication.
-> To generate a certificate run `cd android && ./gradlew signingReport` and copy the SHA1 from the `debug` key. This generates two variant keys.
-> You can copy the 'SHA1' that belongs to the `debugAndroidTest` variant key option.
+> To generate a certificate run `cd android && ./gradlew signingReport`. This generates two variant keys.
+> You have to copy both 'SHA1' and 'SHA-256' keys that belong to the 'debugAndroidTest' variant key option.
+> Then, you can add those keys to the 'SHA certificate fingerprints' on your app in Firebase console.
 
 Download the `google-services.json` file and place it inside of your project at the following location: `/android/app/google-services.json`.
 

packages/auth/android/src/main/java/io/invertase/firebase/auth/ReactNativeFirebaseAuthModule.java

@@ -44,7 +44,6 @@
 import com.google.firebase.auth.FirebaseAuthInvalidCredentialsException;
 import com.google.firebase.auth.FirebaseAuthProvider;
 import com.google.firebase.auth.FirebaseAuthSettings;
-import com.google.firebase.auth.FirebaseAuthUserCollisionException;
 import com.google.firebase.auth.FirebaseUser;
 import com.google.firebase.auth.FirebaseUserMetadata;
 import com.google.firebase.auth.GetTokenResult;