Go directly to the Sensei Home page in WP admin after completing the Sensei onboarding flow

[donnapep]

What

Once a user completes the Sensei onboarding flow, they should be taken to Sensei's Home page so that they can complete the onboarding checklist.

Why

Currently, the user is taken to the My Home page in Calypso after completing the flow, where they are presented with a Site setup onboarding checklist, not the Sensei-specific one. Calypso is also difficult to navigate, and it's easy to get lost when you're constantly switching in and out of Calypso vs. WP admin.

How

Woo has already done this in their ecommerce flow. However, they take the user to a top-level Home page, whereas we'd like to take them to Sensei's Home page if possible (at least for now).

Dependent on #85270, as I don't think this should ship before that change.