fix group local_path

as per Lists, we need to override get_remote_id to remove the user from the URL

bookwyrm/models/group.py

@@ -17,6 +17,10 @@ class Group(BookWyrmModel):
     description = fields.TextField(blank=True, null=True)
     privacy = fields.PrivacyField()
 
+    def get_remote_id(self):
+        """don't want the user to be in there in this case"""
+        return f"https://{DOMAIN}/group/{self.id}"
+
 class GroupMember(models.Model):
     """Users who are members of a group"""
     created_date = models.DateTimeField(auto_now_add=True)