Update wikimedia/less.php dependency #16976

Description:

We need to update wikimedia/less.php as the new release has some fixes for PHP 8.

I had to overwrite the composer platform config to PHP 7.2.9, as wikimedia/less.php requires PHP 7.2.9.
It should work with 7.2.5 as well, see https://github.com/wikimedia/less.php/issues/50#issuecomment-747566164

refs #16897

Review

• [ ] Functional review done
• [ ] Usability review done (is anything maybe unclear or think about anything that would cause people to reach out to support)
• [ ] Security review done see checklist
• [ ] Code review done
• [ ] Tests were added if useful/possible
• [ ] Reviewed for breaking changes
• [ ] Developer changelog updated if needed
• [ ] Documentation added if needed
• [ ] Existing documentation updated if needed