Explore if it's feasible to display the chat for the users since the first step of the Sensei onboarding flow

## What

The Sensei onboarding flow only displays the chat on the checkout step. It would be nice to have the chat since the first steps.

## To confirm

Is it technically feasible? And is it okay for HEs?

## Why

Users might have questions before the checkout, when they are choosing the site name, the domain, and the plan.

## Context

p6rkRX-74d-p2

Start by tracing the Sensei onboarding flow from the site-name, domain, and plan steps through checkout, where the chat is currently displayed. Confirm whether showing it from the first step is technically feasible and acceptable for HEs; done means a documented feasibility decision and agreed scope.

Written by the indexing model from the issue text.