client: return total wait duration in resource interceptor OnRequestWait call (#7488)

[ti-chi-bot]

This is an automated cherry-pick of #7488

What problem does this PR solve?

Issue Number: ref #5851

What is changed and how does it work?

return total wait duration in resource interceptor OnRequestWait call so we can track the wait duration in tidb slow log.

Check List

Tests

• Unit test

Code changes

Side effects

Related changes

• PR to update pingcap/docs/pingcap/docs-cn:
• PR to update pingcap/tiup:
• Need to cherry-pick to the release branch

Release note

None.

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• CabinfeverB
• HuSharp

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[codecov]

Codecov Report

Merging #7794 (c36afc2) into release-7.5 (a276843) will decrease coverage by 0.03%.
Report is 3 commits behind head on release-7.5.
The diff coverage is 46.51%.

Additional details and impacted files

@@               Coverage Diff               @@
##           release-7.5    #7794      +/-   ##
===============================================
- Coverage        74.62%   74.60%   -0.03%     
===============================================
  Files              443      443              
  Lines            47923    47952      +29     
===============================================
+ Hits             35764    35775      +11     
- Misses            8996     9014      +18     
  Partials          3163     3163              

Flag	Coverage Δ
unittests	74.60% <46.51%> (-0.03%)	⬇️

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[HuSharp]

LGTM!

[CabinfeverB]

/merge

[ti-chi-bot]

@CabinfeverB: It seems you want to merge this PR, I will help you trigger all the tests:

/run-all-tests

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[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: c36afc2