GlSorting has its own story, so there's no need to have another one
under "button".

This makes `GlCollapsibleListbox` render correctly in button groups.
`GlDisclosureDropdown` already did, and the styling used to implement
that was moved to the base dropdown implementation.

Addresses gitlab-org/gitlab-ui#2263.

The previous commit makes these classes redundant.

- This helps the maintainability of this helper component
- !3908 (comment 1791331763)

refactor: Move common story options into TokensStory component

See merge request gitlab-org/gitlab-ui!4002



Merged-by: Scott de Jonge <sdejonge@gitlab.com>
Approved-by: Scott de Jonge <sdejonge@gitlab.com>
Reviewed-by: Scott de Jonge <sdejonge@gitlab.com>
Co-authored-by: Paul Slaughter <pslaughter@gitlab.com>

feat(GlCollapsibleListbox): Render correctly in button group

Closes #2263

See merge request gitlab-org/gitlab-ui!3966



Merged-by: Enrique Alcántara <ealcantara@gitlab.com>
Approved-by: Olena Horal-Koretska <ohoralkoretska@gitlab.com>
Approved-by: Austin Regnery <aregnery@gitlab.com>
Approved-by: Enrique Alcántara <ealcantara@gitlab.com>
Reviewed-by: Mark Florian <mflorian@gitlab.com>
Reviewed-by: Olena Horal-Koretska <ohoralkoretska@gitlab.com>
Co-authored-by: Mark Florian <mflorian@gitlab.com>

# [77.3.0](gitlab-org/gitlab-ui@v77.2.0...v77.3.0) (2024-02-28)

### Features

* **GlCollapsibleListbox:** Render correctly in button group ([aa7b93ab](gitlab-org/gitlab-ui@aa7b93ab))