[Bug]: `querynode_entity_num` is not accurate

[congqixia]

Is there an existing issue for this?

• [X] I have searched the existing issues

Environment

- Milvus version: 4de063a & 2.4.1
- Deployment mode(standalone or cluster):
- MQ type(rocksmq, pulsar or kafka):    
- SDK version(e.g. pymilvus v2.0.0rc2):
- OS(Ubuntu or CentOS): 
- CPU/Memory: 
- GPU: 
- Others:

Current Behavior

In worker node, the metrics is not cleaned up In some extreme case, metrics value went negative

Expected Behavior

Entity number shall be accurate

Steps To Reproduce

No response

Milvus Log

No response

Anything else?

No response

[lblblong]

这里确实做的比较粗糙，后面找时间再慢慢修改