Fix: Remove the pagination from the search and retrieval pages. (#15942)

### What problem does this PR solve?

Fix: Remove the pagination from the search and retrieval pages.

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

api/apps/services/dataset_api_service.py

@@ -1440,6 +1440,7 @@ async def search_datasets(tenant_id: str, req: dict):
         except Exception:
             logging.warning("search_datasets KG retrieval failed: datasets=%s tenant=%s", kb_ids, tenant_id, exc_info=True)
     ranks["chunks"] = settings.retriever.retrieval_by_children(ranks["chunks"], tenant_ids)
+    ranks["total"] = len(ranks["chunks"])
 
     for c in ranks["chunks"]:
         c.pop("vector", None)