feat(GlFilteredSearch): Improve dropdown styles

mentioned in commit 004df66c

mentioned in merge request status-page!903

mentioned in merge request gitlab!150344 (merged)

mentioned in merge request gitlab-org/frontend/pajamas-adoption-scanner!323 (merged)

mentioned in merge request gitlab-org/gitlab-services/design.gitlab.com!3827 (merged)

mentioned in merge request gitlab-org/frontend/playground/accessibility-scanner!34 (merged)

mentioned in merge request gitlab-org/editor-extensions/gitlab-jetbrains-plugin!486 (closed)

mentioned in merge request gitlab-org/editor-extensions/gitlab-jetbrains-plugin!570 (merged)