Problem/Motivation
Follow-up to #3087644: Remove Drupal 8 updates up to and including 88**.
Blocks Drupal 9 beta.
If we decide to keep the update and re-add tests for it, that will be easiest once #3095333: Extend filled database dump with new stable modules and content for them is in core.
If we decide to remove the update, we may want special messaging for workspaces module following #3098475: Add more strict checking of hook_update_last_removed() and better explanation to explicitly point out that people need to update to 8.8.2 first if they hit this condition.
Proposed resolution
1. Remove the update and post update
2. Add a workspace-specific message in #3098475: Add more strict checking of hook_update_last_removed() and better explanation to inform any workspaces 8.8.0 users trying to go direct to 9.0.0, that they need to update to 8.8.2 or higher first.