Merge branch '456032-remove-trial_discover_page-css-from-page-bundle' into 'master'

Remove page_bundles/trial_discover_page.css from page bundle

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/175611



Merged-by: Max Fan <mfan@gitlab.com>
Approved-by: Max Fan <mfan@gitlab.com>
Co-authored-by: rliu-gl <rliu@gitlab.com>