Deleted Keycloak groups remain in OpenCloud with stale memberships

[ScharfViktor]

tested against OpenCloud v7.0.0-rc.0

Steps:

• run COMPOSE_FILE=docker-compose.yml:weboffice/collabora.yml:traefik/opencloud.yml:traefik/collabora.yml:idm/ldap-keycloak.yml:traefik/ldap-keycloak.yml
• Log in to Keycloak.
• Create a new group.
• Add a user to the group.
• Verify that the group appears in OpenCloud.
• Delete the group in Keycloak.

Actual result:

• group is removed from Keycloak.
• group still exists in OpenCloud.
• user still sees themselves as a member of the deleted group.

Case with deleting user -works fine

Expected: group should be removed from OpenCloud.