Follow-up from "Fix initial user selection after search"

The following discussion from !162776 (merged) should be addressed:

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

  thought (non-blocking):

  Looking across the code base, this seems to be a common pattern. I wonder if it is worth abstracting into a util and using widely...

  note: this one seems really close to what we are doing overall here https://gitlab.com/gitlab-org/gitlab/-/blob/d798c401a49a9591c08089f370fa4036dd1bdfec/app/assets/javascripts/vue_shared/components/listbox_input/listbox_input.vue#L103-103 🤔