(ios) Return rawNonce in credential result when authentication with A…

[TheNotorius0]

…pple is successful.

PR Type

What kind of change does this PR introduce?

• [ ] Bugfix
• [x] Feature
• [ ] Code style update (formatting, local variables)
• [ ] Refactoring (no functional changes, no api changes)
• [ ] Documentation changes
• [ ] Other... Please describe:

PR Checklist

Please check your PR fulfills the following requirements:

Bugfixes:

• [ ] Regression testing has been carried out using the example project to ensure the intended bug is fixed and no regression bugs have been inadvertently introduced.

New features/enhancements:

• [x] Exhaustive testing has been carried out for the new functionality
• [ ] Regression testing has been carried out to ensure no existing functionality is adversely affected
• [ ] Documentation has been added / updated
• [ ] The example project has been update to validate/demonstrate the new functionality.

What is the purpose of this PR?

Fixes https://github.com/dpa99c/cordova-plugin-firebasex/issues/867, which was a follow-up of https://github.com/dpa99c/cordova-plugin-firebasex/issues/857

Basically, after you use FirebasePlugin.authenticateUserWithApple() you get a credential object. This object can be used to login with the Firebase javascript SDK:

const appleWebCredentials = appleProvider.credential({idToken: credential.idToken, rawNonce: credential.rawNonce});
firebase.auth().signInWithCredential(appleWebCredentials);

Unfortunately, the rawNonce is not passed from the plugin. This pull request fixes it.

Does this PR introduce a breaking change?

• [ ] Yes
• [x] No

What testing has been done on the changes in the PR?

What testing has been done on existing functionality?

Other information