Fix kb mcp api

[moria97]

1. 修复mcp api contract
2. 搜索结果不返回bbox信息
3. 去除不相关的trace span (openai embedding / elasticsearch
4. trace exporter 设置compression gzip

[github-actions]

☂️ Python Coverage

current status: ✅

Overall Coverage

Lines	Covered	Coverage	Threshold	Status
12717	5233	41%	0%	🟢

New Files

No new covered files...

Modified Files

File	Coverage	Status
backend/api/v1/mcp/kb_retriever_tool.py	55%	🟢
backend/app/main.py	84%	🟢
backend/extensions/trace/grpc_exporter.py	46%	🟢
backend/extensions/trace/http_exporter.py	39%	🟢
backend/extensions/trace/trace_context_middleware.py	96%	🟢
backend/service/knowledgebase/rag_service.py	44%	🟢
backend/tools/utils/vectordb_retrieval.py	55%	🟢
TOTAL	60%	🟢

updated for commit: 7fef894 by action🐍