[Feat] add a filter() method for the lists

[guelate]

What:

Hello I'm a student and I would like to participate I propose to add a filter() method for lists

Example code:

Why: it's useful to sort and select the elements of a list.

Originally posted by @guelate in https://github.com/less/less.js/discussions/3704

[abhijain2003]

what you are trying to achieve, could you elaborate

[matthew-dean]

what you are trying to achieve, could you elaborate

Same question. It's unclear why someone would ever need to filter a list by the string length of values.