fix: nacos stop cannot cancel subscription

[chenliang]

Description (what this PR does / why we need it):

nacos stop cannot cancel subscription. causing the callback channel to be blocked, the new Watcher cannot receive the callback notification and gets the connection timeout

Which issue(s) this PR fixes (resolves / be part of):

Other special notes for the reviewers:

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 81.64%. Comparing base (1ab258e) to head (a87785e).

❗ Current head a87785e differs from pull request most recent head 9135ba1. Consider uploading reports for the commit 9135ba1 to get more accurate results

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Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3173      +/-   ##
==========================================
+ Coverage   81.54%   81.64%   +0.09%     
==========================================
  Files          91       91              
  Lines        4167     4167              
==========================================
+ Hits         3398     3402       +4     
+ Misses        589      587       -2     
+ Partials      180      178       -2     

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