refactor(LmqBrokerStatsManager): Refactor Redundant Code in LmqBrokerStatsManager

[asapple]

Extracted the duplicated logic of replacing group and topic with LMQ_PREFIX based on configuration into a common method, improving code structure and maintainability.

Which Issue(s) This PR Fixes

Fixes #9033

Brief Description

Refactor the LmqBrokerStatsManager class by extracting the common logic that modifies the group and topic values into a private helper method.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 12 lines in your changes missing coverage. Please review.

Project coverage is 47.78%. Comparing base (d1fd7af) to head (7502b52).

Files with missing lines	Patch %	Lines
...he/rocketmq/store/stats/LmqBrokerStatsManager.java	0.00%	12 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             develop    #9034   +/-   ##
==========================================
  Coverage      47.77%   47.78%           
+ Complexity     11827    11822    -5     
==========================================
  Files           1305     1305           
  Lines          91405    91344   -61     
  Branches       11748    11721   -27     
==========================================
- Hits           43673    43649   -24     
+ Misses         42324    42285   -39     
- Partials        5408     5410    +2     

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