When creating a new user group, the permissions for the new group will now be pre-populated with the same permissions as the "default user group".
This is achieved by removing the separate `AddGroupModal` and instead using the `EditGroupModal` for both creating and editing groups. When creating a new group, the `EditGroupModal` is now pre-populated with the default permissions, saving administrators from having to manually configure them each time.
This change simplifies the codebase by removing a redundant component and directly addresses the user's request to streamline the group creation process.