Move 'timeout' to common folder (#10983)

### What problem does this PR solve?

As title.

### Type of change

- [x] Refactoring

Signed-off-by: Jin Hai <haijin.chn@gmail.com>

agent/tools/retrieval.py

@@ -25,7 +25,7 @@ from api.db.services.dialog_service import meta_filter
 from api.db.services.knowledgebase_service import KnowledgebaseService
 from api.db.services.llm_service import LLMBundle
 from api import settings
-from api.utils.api_utils import timeout
+from common.connection_utils import timeout
 from rag.app.tag import label_question
 from rag.prompts.generator import cross_languages, kb_prompt, gen_meta_filter