Revert Clean-up pending-members alert in usage seats

What does this MR do and why?

Revert "Merge branch '431187-clean-up-pending-members-alert-in-seats-app' into 'master'"

This reverts merge request !141590 (merged)

After discussion in #431187 (comment 1733236523) , a decision was made to temporary roll back this change, in order to fix https://gitlab.com/gitlab-org/gitlab/-/issues/334381, and then fine-tune the new banner in scope of #438745 (closed)

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

Screenshots are required for UI changes, and strongly recommended for all other merge requests.

Before	After

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.