Migrate checkboxes to Pajamas form

What does this MR do and why?

Migrate form on pages settings page to Pajamas form

Related to #358340 (closed)

Screenshots or screen recordings

Before	After
disabled (yes, it is not clickable)	disabled
enabled	enabled

How to set up and validate locally

1. Set Gitlab.config.pages.external_https or Gitlab.config.pages.external_http to true
2. Open a project of your choice and navigate to Settings -> Pages (http://localhost:3000/flightjs/Flight/pages)
3. To check disabled state change the helper method #pages_https_only_disabled?

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.