Restore the user_id property for fully resolved users (#371)

When resolving a PeerUser to a full_user, resolve_groups will now re-insert the original user_id property in the generated dictionary (so the ID is always accessible at the same JSON path whether or not we chose to resolve references).  This mirrors the existing behaviour for resolving channels.

datasources/telegram/search_telegram.py

@@ -407,6 +407,7 @@ async def resolve_groups(self, client, message):
                         self.details_cache[value["user_id"]] = SearchTelegram.serialize_obj(user)
 
                     resolved_message[key] = self.details_cache[value["user_id"]]
+                    resolved_message[key]["user_id"] = value["user_id"]
                 else:
                     resolved_message[key] = await self.resolve_groups(client, value)