[ISSUE #10046] Fix lock leak risk in sendHeartbeatToBroker

[yx9o]

Fixes #10046 .

[codecov-commenter]

Codecov Report

❌ Patch coverage is 50.00000% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 48.90%. Comparing base (50e7ffa) to head (ae7a0c3).

Files with missing lines	Patch %	Lines
...rocketmq/client/impl/factory/MQClientInstance.java	50.00%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@              Coverage Diff              @@
##             develop   #10047      +/-   ##
=============================================
- Coverage      48.96%   48.90%   -0.07%     
+ Complexity     13355    13337      -18     
=============================================
  Files           1373     1373              
  Lines          99700    99700              
  Branches       12887    12887              
=============================================
- Hits           48820    48758      -62     
- Misses         44974    45024      +50     
- Partials        5906     5918      +12     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.