[ISSUE #8712] Set namesrvAddrChoosed to null if choosed addr is not exist.

[qianye1001]

…ient is no longer in use, a new channel connection will be created.

Which Issue(s) This PR Fixes

Fixes #8712

Brief Description

How Did You Test This Change?

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 1 line in your changes missing coverage. Please review.

Project coverage is 47.44%. Comparing base (280804c) to head (7784631).

Files with missing lines	Patch %	Lines
...e/rocketmq/remoting/netty/NettyRemotingClient.java	0.00%	1 Missing ⚠️

Additional details and impacted files

@@              Coverage Diff              @@
##             develop    #8713      +/-   ##
=============================================
- Coverage      47.46%   47.44%   -0.03%     
+ Complexity     11543    11527      -16     
=============================================
  Files           1278     1278              
  Lines          89524    89524              
  Branches       11509    11509              
=============================================
- Hits           42496    42472      -24     
- Misses         41805    41822      +17     
- Partials        5223     5230       +7     

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[fuyou001]

CR need