Clicking "Customize Search Widget" from My Plan page just takes me to /wp-admin/widgets.php

#### Steps to reproduce the issue

1. On a site with Jetpack Professional, go to /wp-admin/admin.php?page=jetpack#/my-plan
2. Scroll down to 'Jetpack Search'. Click on Activate Search (if necessary) then 'Customize Search Widget'
4. You land on /wp-admin/widgets.php

#### What I expected
I expected to be taken to a UI which has the widget open, able to be customized and previewed (perhaps in the customizer?)

#### What happened instead
Taken to a widgets page, where there is already a search widget in the sidebar that is NOT the "advanced" search widget I was promised.

**Screenshots**

Reproduce the flow from /wp-admin/admin.php?page=jetpack#/my-plan, activating Jetpack Search if needed, and clicking “Customize Search Widget.” Start by tracing where that action redirects to /wp-admin/widgets.php. Done means it opens the promised advanced search widget customization and preview UI rather than the standard sidebar widget.

Written by the indexing model from the issue text.