Support for identifier first authenticator in React SDK

[DonOmalVindula]

Description:
$subject

Currently, there's no UI component in the React SDK for the Identifier First authenticator even though this is supported in the API-based auth APIs. Therefore we need to implement this authenticator.

Steps to reproduce:

1. Create an application with API-based auth enabled.
2. Add identifier first as a step in the login flow of the application.
3. Attempt to login to the application. It will not show any UI for the identifier first authenticator step.

[DonOmalVindula]

Closing as this is done