tests: fix TestKeyspaceGroupSplit

[rleungx]

What problem does this PR solve?

Issue Number: ref #9806.

What is changed and how does it work?

Check List

Tests

• Unit test

Release note

None.

[ti-chi-bot]

@rleungx: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
non-block/pull-unit-test-next-gen	e7c5ad1	link	false	/test pull-unit-test-next-gen

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 76.87%. Comparing base (1d4b63b) to head (e7c5ad1).
⚠️ Report is 3 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #9815   +/-   ##
=======================================
  Coverage   76.86%   76.87%           
=======================================
  Files         491      491           
  Lines       78311    78311           
=======================================
+ Hits        60197    60198    +1     
- Misses      14422    14431    +9     
+ Partials     3692     3682   -10     

Flag	Coverage Δ
unittests	76.87% <ø> (+<0.01%)	⬆️

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[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

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

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Needs approval from an approver in each of these files:

• OWNERS [JmPotato,lhy1024]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2025-10-11 03:50:18.861312056 +0000 UTC m=+498607.892411383: ☑️ agreed by lhy1024.
• 2025-10-11 06:31:59.536349276 +0000 UTC m=+508308.567448594: ☑️ agreed by JmPotato.