fix: [2.4] Deep copy ImportTask.segmentsInfo to prevent data race (#34090)

[congqixia]

Cherry-pick from master
pr: #34090
See also #34089

[sre-ci-robot]

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 81.78%. Comparing base (1168e8c) to head (727dc3e).
Report is 9 commits behind head on 2.4.

Additional details and impacted files

@@            Coverage Diff             @@
##              2.4   #34126      +/-   ##
==========================================
- Coverage   81.83%   81.78%   -0.06%     
==========================================
  Files        1005     1013       +8     
  Lines      130111   129934     -177     
==========================================
- Hits       106479   106266     -213     
- Misses      19644    19670      +26     
- Partials     3988     3998      +10     

Files	Coverage Δ
internal/datanode/importv2/task_import.go	86.50% <100.00%> (+0.32%)	⬆️
internal/datanode/importv2/task_l0_import.go	78.68% <100.00%> (+0.53%)	⬆️
internal/datanode/importv2/task_l0_preimport.go	84.31% <100.00%> (ø)
internal/datanode/importv2/task_preimport.go	91.45% <100.00%> (ø)

... and 219 files with indirect coverage changes

[weiliu1031]

/lgtm