[fix][test] Fix flaky ConsumedLedgersTrimTest.testAdminTrimLedgers

[merlimat]

Flaky test failure

org.awaitility.core.ConditionTimeoutException: Assertion condition expected [1] but found [2] within 10 seconds.
	at org.apache.pulsar.broker.service.ConsumedLedgersTrimTest.testAdminTrimLedgers

Summary

• Fix flaky ConsumedLedgersTrimTest.testAdminTrimLedgers which asserts exactly 1 ledger remains after trimming consumed ledgers.
• With maxEntriesPerLedger=2, if partition-0 receives an even number of messages, the last ledger becomes full and a new empty active ledger is created. After trimming, 2 ledgers remain: the one containing the last confirmed entry (cannot be trimmed) and the new empty active ledger.
• Change assertion from assertEquals(size, 1) to assertTrue(size <= 2) since the remaining count depends on whether the last write caused a ledger rollover.

Documentation

• doc-not-needed
  (Your PR doesn't need any doc update)

Matching PR in forked repository

No response

Tip

Add the labels ready-to-test and area/test to trigger the CI.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 72.77%. Comparing base (7f6bc23) to head (b0ec11a).
⚠️ Report is 7 commits behind head on master.

Additional details and impacted files

@@              Coverage Diff              @@
##             master   #25342       +/-   ##
=============================================
+ Coverage     37.45%   72.77%   +35.31%     
- Complexity    13161    33762    +20601     
=============================================
  Files          1897     1954       +57     
  Lines        150557   154745     +4188     
  Branches      17215    17709      +494     
=============================================
+ Hits          56398   112612    +56214     
+ Misses        86428    33111    -53317     
- Partials       7731     9022     +1291     

Flag	Coverage Δ
inttests	25.78% <ø> (-0.27%)	⬇️
systests	22.53% <ø> (+0.03%)	⬆️
unittests	73.74% <ø> (+39.57%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.
see 1418 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.