Focus color picker input when selecting input label

The following discussion from !78281 (merged) should be addressed:

• @pedroms started a discussion: (+1 comment)

  @wwwjon ⚠️ issue (behavior): When clicking on an input label, the corresponding input should be focused. Right now, clicking on the labels doesn't focus the inputs.

  

Implementation Guide

https://gitlab.com/gitlab-org/gitlab/-/blob/master/app/assets/javascripts/vue_shared/components/color_picker/color_picker.vue