core: skip tiflash engine role key check (#9849)

[ti-chi-bot]

This is an automated cherry-pick of #9849

What problem does this PR solve?

Issue Number: Close #9848

What is changed and how does it work?

Check List

Tests

• Unit test

Release note

None.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 78.70%. Comparing base (5bbec7c) to head (429ed63).
⚠️ Report is 4 commits behind head on release-nextgen-20251011.

Additional details and impacted files

@@                     Coverage Diff                      @@
##           release-nextgen-20251011    #9877      +/-   ##
============================================================
- Coverage                     78.73%   78.70%   -0.04%     
============================================================
  Files                           491      491              
  Lines                         65896    66094     +198     
============================================================
+ Hits                          51880    52016     +136     
- Misses                        10340    10390      +50     
- Partials                       3676     3688      +12     

Flag	Coverage Δ
unittests	78.70% <100.00%> (-0.04%)	⬇️

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[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

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

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• OWNERS [lhy1024,rleungx]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2025-10-28 06:36:32.250273537 +0000 UTC m=+1372098.327526096: ☑️ agreed by lhy1024.
• 2025-10-28 06:41:54.334496625 +0000 UTC m=+1372420.411749185: ☑️ agreed by rleungx.

[rleungx]

/override pull-unit-test-next-gen

[ti-chi-bot]

@rleungx: Overrode contexts on behalf of rleungx: pull-unit-test-next-gen

Details

In response to this:

/override pull-unit-test-next-gen

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