chore: upgrade Wikimedia/less.php to 4.1

[imorland]

Although the less.js version remains at 2.5.3 :( I still think it worthwhile to bump to 4.x here, at least until we decide if LESS will be kept, or replaced with SCSS, etc.

Changes since 3.2.1:

4.1.0

• Add support for @supports blocks. (Anne Tomasevich) T332923
• Less_Parser: Returning a URI from SetImportDirs() callbacks is now optional. (Timo Tijhof)

4.0.0

• Remove support for PHP 7.2 and 7.3. Raise requirement to PHP 7.4+.
• Remove support for cache_method=php and cache_method=var_export, only the faster and more secure cache_method=serialize is now available. The built-in cache remains disabled by default.
• Fix url(#myid) to be treated as absolute URL. T331649
• Fix "Undefined property" PHP 8.1 warning when calc() is used with CSS var(). T331688
• Less_Parser: Improve performance by removing MatchFuncs and NewObj overhead. (Timo Tijhof)

wikimedia/less.php@v3.2.1...v4.1.0