enhance: [2.4] Remove segment-level tag from monitoring metrics

[bigsheeper]

When there are a large number of segments, the metrics consume a lot of memory. This PR Remove segment-level tag from monitoring metrics.

issue: #37636

pr: #37696

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 80.58%. Comparing base (cdf703a) to head (a6d4fc1).
Report is 2 commits behind head on 2.4.

Additional details and impacted files

@@            Coverage Diff             @@
##              2.4   #37737      +/-   ##
==========================================
- Coverage   80.65%   80.58%   -0.07%     
==========================================
  Files        1069     1069              
  Lines      166900   166878      -22     
==========================================
- Hits       134605   134485     -120     
- Misses      27902    27970      +68     
- Partials     4393     4423      +30     

Files with missing lines	Coverage Δ
internal/datacoord/index_meta.go	95.59% <100.00%> (-0.42%)	⬇️
internal/datacoord/meta.go	89.43% <100.00%> (-0.03%)	⬇️
internal/metastore/kv/datacoord/kv_catalog.go	74.51% <100.00%> (-0.08%)	⬇️
pkg/metrics/datacoord_metrics.go	51.92% <ø> (-11.85%)	⬇️
pkg/metrics/metrics.go	100.00% <ø> (ø)

... and 33 files with indirect coverage changes

[congqixia]

/lgtm

[sre-ci-robot]

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