add clarity on how to handle confirmSignIn() and signIn() API responses for nextStep property

[cwomack]

Describe the content issue:
A clear and concise description of what the content issue is. Is there content missing or is there incorrect content?

We need to update the confirmSignIn() documentation to better clarify how to handle when this API returns CONFIRM_SIGN_IN_WITH_NEW_PASSWORD_REQUIRED as the nextStep. This is described in detail within the amplify-js issue #13598.

URL page where content issue is:
https://docs.amplify.aws/react/build-a-backend/auth/connect-your-frontend/sign-in/#using-the-signin-api

[mklaver]

Apologies if this is the wrong place for this, but will the docs also be updated for the other languages or since this came from the amplify-js project originally just the React/JS pages will be updated? I'm having the exact same issue as the original posters from the amplify-js thread but in Swift.