fix mongo impl

lightrag/kg/mongo_impl.py

@@ -2,11 +2,14 @@ import os
 from tqdm.asyncio import tqdm as tqdm_async
 from dataclasses import dataclass
 import pipmaster as pm
-import np
+import numpy as np
 
 if not pm.is_installed("pymongo"):
     pm.install("pymongo")
 
+if not pm.is_installed("motor"):
+    pm.install("motor")
+
 from pymongo import MongoClient
 from motor.motor_asyncio import AsyncIOMotorClient
 from typing import Union, List, Tuple