client: use defer for cancel

[rleungx]

What problem does this PR solve?

Issue Number: Ref #4399.

What is changed and how does it work?

Some functions may cancel the context twice. This PR uses defer to manage the cancellation of the context.

Check List

Tests

• Unit test

Release note

None.

[codecov]

Codecov Report

Attention: Patch coverage is 87.50000% with 1 line in your changes missing coverage. Please review.

Project coverage is 77.48%. Comparing base (3f32f54) to head (18346ad).
Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #8520      +/-   ##
==========================================
+ Coverage   77.40%   77.48%   +0.07%     
==========================================
  Files         472      472              
  Lines       61821    61741      -80     
==========================================
- Hits        47854    47839      -15     
+ Misses      10400    10335      -65     
  Partials     3567     3567              

Flag	Coverage Δ
unittests	77.48% <87.50%> (+0.07%)	⬆️

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[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: lhy1024, okJiang

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• OWNERS [lhy1024]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-08-13 03:29:35.982518166 +0000 UTC m=+238660.685987810: ☑️ agreed by okJiang.
• 2024-08-13 03:42:50.891329689 +0000 UTC m=+239455.594799329: ☑️ agreed by lhy1024.