Removing a group through the HTTP API does not remove the group completely

[Alienmaster]

Describe the bug When removing a group through the HTTP API call deleteGroup and listing the groups with listAllGroups the group is still in the list. To Reproduce Steps to reproduce the behavior:

1. Start a local etherpad instance with an API-KEY
2. Create a group with createGroup
3. Remove the group with deleteGroup
4. List the existing groups with listAllGroups

Expected behavior listAllGroups should return an empty list.

Server (please complete the following information):

• Etherpad version: GitHub develop Branch eebdd1eaf14add25e8351137196cb6b3127295d5
• OS: Ubuntu 22.04
• Node.js version (node --version): 20.16.0
• npm version (npm --version): 10.8.1
• Is the server free of plugins: yes