add doc ids to chat (#1944)

### What problem does this PR solve?

### Type of change

- [x] Performance Improvement

api/db/services/dialog_service.py

     attachments = kwargs["doc_ids"].split(",") if "doc_ids" in kwargs else None
     if "doc_ids" in messages[-1]:
         attachments = messages[-1]["doc_ids"]
+        for m in messages[:-1]:
+            if "doc_ids" in m:
+                attachments.extend(m["doc_ids"])
 
     embd_mdl = LLMBundle(dialog.tenant_id, LLMType.EMBEDDING, embd_nms[0])
     if llm_id2llm_type(dialog.llm_id) == "image2text":

rag/nlp/search.py

         es_logger.info("TOTAL: {}".format(self.es.getTotal(res)))
         if self.es.getTotal(res) == 0 and "knn" in s:
             bqry, _ = self.qryr.question(qst, min_match="10%")
+            if req.get("doc_ids"):
+                bqry = Q("bool", must=[])
             bqry = self._add_filters(bqry, req)
             s["query"] = bqry.to_dict()
             s["knn"]["filter"] = bqry.to_dict()