core: oplog: fix uid collection

packages/hydrooj/package.json

@@ -1,6 +1,6 @@
 {
     "name": "hydrooj",
-    "version": "3.3.16",
+    "version": "3.3.17",
     "bin": "bin/hydrooj.js",
     "main": "src/loader",
     "module": "src/loader",

packages/hydrooj/src/model/oplog.ts

@@ -27,7 +27,7 @@ export async function log<T extends Handler>(handler: T, type: string, data: any
         ua: handler.request.headers?.['user-agent'],
         referer: handler.request.headers?.referer,
         args,
-        operator: handler.user?.id,
+        operator: handler.user?._id,
         operateIp: handler.request.ip,
     });
     return res.insertedId;