Fix broken citations in Zilliz Cloud (#4716)

fix broken citations in zilliz cloud vector db

Author: shatfield4

server/utils/vectorDbProviders/zilliz/index.js

@@ -239,7 +239,7 @@ const Zilliz = {
             data: chunk.map((item) => ({
               id: item.id,
               vector: item.values,
-              metadata: chunk.metadata,
+              metadata: item.metadata,
             })),
           });