for cli login: use @npmcli/ci-detect to detect whether in a CI environment

Module: https://www.npmjs.com/package/@npmcli/ci-detect

For ims-cli context:

1. If we are in a CI environment, we print out the CI environment, and do not launch the browser.
2. Print out a warning that various environment variables (which correspond to config values) are not available as the access token needed for cli use in a CI env.

Start by locating the ims-cli login flow and reading how it currently launches the browser. Review @npmcli/ci-detect and identify the environment variables corresponding to the access-token configuration. Done means CI environments report the detected CI provider, skip browser launch, and warn that those variables are unavailable.

Written by the indexing model from the issue text.