Required status checks for preview builds

## Context

We have ~50+ consumers of the `preview-build.yml` workflow.

But not all of them have set it to a required status check.

You can find the full list at https://github.com/elastic/docs-builder/network/dependents?owner=elastic&dependent_type=REPOSITORY&owner=elastic

## Request

Make them all required status checks.

## Tracking

[Google sheet](https://docs.google.com/spreadsheets/d/19DMhcwBTYJWHkDD42W4d8tzUms-CcTKv6QWineCJmSo/edit?gid=0#gid=0) (internal link)