Migrate CSS utils in Global Search

What does this MR do and why?

Migrate CSS utils in Global Search

Migrates legacy utils to Tailwind in Global Search frontend files.

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

No visual change expected.

How to set up and validate locally

This migration was performed using our migration tools from gitlab-ui!4362 (merged) and !154442 (merged) (this one's not yet merged as of writing this).

scripts/frontend/find_frontend_files.mjs app/assets/javascripts/super_sidebar/components/global_search/components/global_search.vue | ./node_modules/@gitlab/ui/bin/migrate_custom_utils_to_tw.bundled.mjs --from-stdin