[FEAT] We need a authenticate.pos() for POS UI extensions server communications

[blanklob]

Issue summary

We need an easy way to query and communicate with POS UI extensions as they dont have any way to access API data, and we need a way to use the Session API from POS with Remix.

More docs here https://shopify.dev/docs/api/pos-ui-extensions/2024-04/server-communication

Session API here: https://shopify.dev/docs/api/pos-ui-extensions/2024-04/apis/session-api

[paulomarg]

Good callout! I'll track this and bring it to the team.

In the interest of transparency, it might be a little while until we implement this since there are some other issues we need to look into :)