fix: [2.5] Remove frequently updating metric to avoid mutex contention

[bigsheeper]

issue: #37630

Reduce the frequency of updateIndexTasksMetrics to avoid holding the mutex for long periods.

pr: #38775

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 69.43%. Comparing base (8bf0f0b) to head (421c49b).
Report is 9 commits behind head on 2.5.

❗ There is a different number of reports uploaded between BASE (8bf0f0b) and HEAD (421c49b). Click for more details.

HEAD has 1 upload less than BASE

Flag	BASE (8bf0f0b)	HEAD (421c49b)
	2	1

Additional details and impacted files

@@             Coverage Diff             @@
##              2.5   #38778       +/-   ##
===========================================
- Coverage   81.07%   69.43%   -11.65%     
===========================================
  Files        1400      298     -1102     
  Lines      197102    26650   -170452     
===========================================
- Hits       159801    18504   -141297     
+ Misses      31678     8146    -23532     
+ Partials     5623        0     -5623     

Components	Coverage Δ
Client	∅ <ø> (∅)
Core	69.43% <ø> (-0.16%)	⬇️
Go	∅ <ø> (∅)

see 1117 files with indirect coverage changes

[mergify]

@bigsheeper cpp-unit-test check failed, comment rerun cpp-unit-test can trigger the job again.

[mergify]

@bigsheeper go-sdk check failed, comment rerun go-sdk can trigger the job again.

[mergify]

@bigsheeper go-sdk check failed, comment rerun go-sdk can trigger the job again.

[bigsheeper]

rerun ut

[mergify]

@bigsheeper cpp-unit-test check failed, comment rerun cpp-unit-test can trigger the job again.

[czs007]

rerun cpp-unit-test

[czs007]

/approve
/lgtm

[sre-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: bigsheeper, czs007

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