[Feedback] Add Clarification on Mutable vs Writable attributes

**Page**: [`/cli/auth/import`](https://docs.amplify.aws/cli/auth/import)

**Feedback**:
For federated sign in, confusion on mutable and writable attributes causes an issue when attempting subsequent logins

https://github.com/aws-amplify/amplify-js/issues/3526#issuecomment-1460962106