bugfix: clear the listener map of zk registry

[ls9527]

Ⅰ. Describe what this PR did

在恢复之前清除监听器映射， 否则每次调用恢复， 会倒是监听器的映射翻倍。

就一句代码， 水个PR

Ⅱ. Does this pull request fix one issue?

Ⅲ. Why don't you add test cases (unit test/integration test)?

Ⅳ. Describe how to verify it

Ⅴ. Special notes for reviews

[codecov-io]

Codecov Report

Merging #3254 (6eb1bbd) into develop (be83b1e) will decrease coverage by 0.00%.
The diff coverage is 0.00%.

@@              Coverage Diff              @@
##             develop    #3254      +/-   ##
=============================================
- Coverage      50.87%   50.87%   -0.01%     
- Complexity      3280     3281       +1     
=============================================
  Files            612      612              
  Lines          20113    20114       +1     
  Branches        2519     2518       -1     
=============================================
  Hits           10233    10233              
  Misses          8853     8853              
- Partials        1027     1028       +1     

Impacted Files	Coverage Δ	Complexity Δ
...very/registry/zk/ZookeeperRegisterServiceImpl.java	60.46% <0.00%> (-0.48%)	26.00 <0.00> (ø)
...o/seata/server/coordinator/DefaultCoordinator.java	54.63% <0.00%> (-0.52%)	28.00% <0.00%> (-1.00%)
...in/java/io/seata/server/session/GlobalSession.java	82.72% <0.00%> (-0.46%)	70.00% <0.00%> (-1.00%)
...torage/file/store/FileTransactionStoreManager.java	57.41% <0.00%> (+0.64%)	29.00% <0.00%> (+1.00%)

[xingfudeshi]

LGTM.

[funky-eyes]

LGTM