Update user_select to emit short id version of selected items

The following discussion from !176523 (merged) should be addressed:

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

  thought (non-blocking): this does fix it, but would there not be a way to make sure the skip_ci_selector.vue always gets simple IDs instead of GraphQLIDs from the user_select.vue so we don't need this conversion?