Remove expanding (zooming) effect on screenshots in installation assistant

Originally created by @sajolida on #14678 (Redmine)

See #11527 (closed) and #11527 (comment 53732).

This corresponds to the “screenshot” CSS class.

It should be easy to remove without breaking translations.

Feature Branch: web/14678-remove-zooming-effect

Related issues

• Related to #11527 (closed)
• Blocks #15392 (closed)
• Blocks #15411 (closed)