Add frontend scripts to assets hash calculation

When https://gitlab.com/gitlab-org/gitlab/-/merge_requests/154544
changed `scripts/frontend/tailwind_all_the_way.mjs`, it modified the
Tailwind CSS but `GITLAB_ASSETS_HASH` was not updated.

To avoid this issue, include all the JavaScript scripts in
`scripts/frontend`.

Relates to
https://gitlab.com/gitlab-com/gl-infra/production/-/issues/18107

Changelog: fixed