Add pagerank to KB. (#3809)

### What problem does this PR solve?

#3794

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

api/db/services/task_service.py

@@ -53,6 +53,7 @@ class TaskService(CommonService):
             Knowledgebase.tenant_id,
             Knowledgebase.language,
             Knowledgebase.embd_id,
+            Knowledgebase.pagerank,
             Tenant.img2txt_id,
             Tenant.asr_id,
             Tenant.llm_id,