Merge branch '425052-migrate-dropdown-to-collapsible-listbox' into 'master'

Make variable value listbox searchable

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/143529



Merged-by: Kushal Pandya <kushal@gitlab.com>
Approved-by: Kushal Pandya <kushal@gitlab.com>
Approved-by: Alex Pennells <apennells@gitlab.com>
Approved-by: Miguel Rincon <mrincon@gitlab.com>
Reviewed-by: Kushal Pandya <kushal@gitlab.com>
Reviewed-by: Miguel Rincon <mrincon@gitlab.com>
Reviewed-by: Miranda Fluharty <mfluharty@gitlab.com>
Co-authored-by: Miranda Fluharty <mfluharty@gitlab.com>