optimize: optimize client channel alive check

[funky-eyes]

• I have registered the PR changes.

Ⅰ. Describe what this PR did

Ⅱ. Does this pull request fix one issue?

fixes #4002

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

Ⅳ. Describe how to verify it

Ⅴ. Special notes for reviews

[codecov-commenter]

Codecov Report

Merging #4013 (21d7dae) into develop (f028831) will increase coverage by 0.13%.
The diff coverage is 43.15%.

❗ Current head 21d7dae differs from pull request most recent head b30c3bf. Consider uploading reports for the commit b30c3bf to get more accurate results

@@              Coverage Diff              @@
##             develop    #4013      +/-   ##
=============================================
+ Coverage      49.34%   49.47%   +0.13%     
- Complexity      3721     3724       +3     
=============================================
  Files            692      692              
  Lines          23419    23404      -15     
  Branches        2902     2903       +1     
=============================================
+ Hits           11555    11579      +24     
+ Misses         10701    10663      -38     
+ Partials        1163     1162       -1     

Impacted Files	Coverage Δ
...io/seata/core/rpc/netty/AbstractNettyRemoting.java	14.28% <0.00%> (ø)
...a/io/seata/discovery/registry/RegistryService.java	0.00% <0.00%> (ø)
...source/exec/mysql/MySQLInsertOrUpdateExecutor.java	31.42% <ø> (-0.04%)	⬇️
...urce/exec/postgresql/PostgresqlInsertExecutor.java	43.75% <0.00%> (ø)
...seata/rm/datasource/undo/AbstractUndoExecutor.java	66.90% <0.00%> (ø)
...ta/spring/boot/autoconfigure/StarterConstants.java	0.00% <ø> (ø)
...figure/properties/registry/RegistryProperties.java	37.50% <0.00%> (-22.50%)	⬇️
.../src/main/java/io/seata/server/env/PortHelper.java	0.00% <0.00%> (ø)
...ure/properties/server/store/StoreDBProperties.java	28.07% <25.00%> (-0.24%)	⬇️
server/src/main/java/io/seata/server/Server.java	75.00% <33.33%> (-5.00%)	⬇️
... and 12 more

[slievrly]

LGTM