enhance: enable task delta cache

[bigsheeper]

When there are many segment tasks in the querycoord scheduler, the traversal in GetSegmentTaskDelta checks becomes time-consuming. This PR adds caching for segment deltas.

issue: #37630

[sre-ci-robot]

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[mergify]

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 81.08%. Comparing base (657550c) to head (72e67a2).
Report is 1 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff             @@
##           master   #39307       +/-   ##
===========================================
+ Coverage   69.63%   81.08%   +11.44%     
===========================================
  Files         299     1406     +1107     
  Lines       26807   198396   +171589     
===========================================
+ Hits        18668   160861   +142193     
- Misses       8139    31883    +23744     
- Partials        0     5652     +5652     

Components	Coverage Δ
Client	79.50% <ø> (∅)
Core	69.63% <ø> (ø)
Go	83.00% <100.00%> (∅)

Files with missing lines	Coverage Δ
internal/querycoordv2/task/scheduler.go	89.10% <100.00%> (ø)

... and 1106 files with indirect coverage changes