[Bug]: Metrics consume a lot of memory

[bigsheeper]

Is there an existing issue for this?

• I have searched the existing issues

Environment

- Milvus version:
- 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

When there are a large number of segments, the metrics consume a lot of memory.

Expected Behavior

Segment-level metrics are unnecessary; collection-level metrics are sufficient.

Steps To Reproduce

No response

Milvus Log

No response

Anything else?

No response

[bigsheeper]

related to: #37630

[xiaofan-luan]

probbaly we don't need segment level tag?

[bigsheeper]

probbaly we don't need segment level tag?

Yes, I will remove it.