test(producer) improve the transaction unit test stability

[duhenglucky]

What is the purpose of the change

XXXXX

Brief changelog

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Verifying this change

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[codecov-io]

Codecov Report

Merging #67 into ctypes will decrease coverage by 1%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           ctypes      #67      +/-   ##
==========================================
- Coverage   80.16%   79.15%   -1.01%     
==========================================
  Files           4        4              
  Lines         595      595              
==========================================
- Hits          477      471       -6     
- Misses        118      124       +6

Impacted Files	Coverage Δ
rocketmq/client.py	62.85% <0%> (-1.91%)	⬇️

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