dm-worker: use run ctx instead global ctx to fix double write

[GMHDBJD]

What problem does this PR solve?

Issue Number: close #7658

What is changed and how it works?

• use runCtx running job
• use kaCtx for keepalive

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Questions

Will it cause performance regression or break compatibility?

Do you need to update user documentation, design documentation or monitoring documentation?

Release note

None

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• buchuitoudegou
• lance6716

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[codecov-commenter]

Codecov Report

Merging #7661 (a7646b1) into master (01e0f31) will increase coverage by 0.0961%.
The diff coverage is 78.2608%.

Additional details and impacted files

Flag	Coverage Δ
cdc	66.2842% <ø> (+0.0348%)	⬆️
dm	52.1414% <82.3529%> (-0.0002%)	⬇️
engine	64.4315% <66.6666%> (+0.6482%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

@@               Coverage Diff                @@
##             master      #7661        +/-   ##
================================================
+ Coverage   59.8250%   59.9212%   +0.0961%     
================================================
  Files           812        812                
  Lines         93078      92927       -151     
================================================
- Hits          55684      55683         -1     
+ Misses        32541      32393       -148     
+ Partials       4853       4851         -2     

[GMHDBJD]

/run-all-tests

[GMHDBJD]

/merge

[ti-chi-bot]

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

Commit hash: a7646b1

[GMHDBJD]

/verify-ci

[fubinzh]

/label needs-cherry-pick-release-6.1

[ti-chi-bot]

In response to a cherrypick label: new pull request created: #7745.