[HelpHub]: Add block variations transformation in block switcher

[femkreations]

Update the pages listed below for the following issue

• [ ] Add block variations transformation in block switcher 50139

List of pages

• [ ] Stack block page
• [ ] Categories block page
• [ ] Tag block page

General

• [ ] Make sure all screenshots are relevant to the latest version
• [ ] Make sure videos, if any, are up to date
• [ ] Add ALT tags for the images
• [ ] Make sure the headings are in sentence case
• [ ] Convert all reusable blocks to a ‘regular block’.
• [ ] Update the changelog at the end of the article