Refactor least active balance algorithm.

[damonxue]

The previous version did not record historical access and could not be used as the least active upstream node.

countMap.keySet().forEach(key -> {
           // After several times, domains in the countMap with only the most frequently visited or none
            if (!domainList.keySet().contains(key)) {
                countMap.remove(key);
            }
        });

Make sure that:

• You have read the contribution guidelines.
• You submit test cases (unit or integration tests) that back your changes.
• Your local test passed ./mvnw clean install -Dmaven.javadoc.skip=true.

[codecov-commenter]

Codecov Report

Merging #4342 (46d3b72) into master (23876bf) will decrease coverage by 0.05%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##             master    #4342      +/-   ##
============================================
- Coverage     68.25%   68.20%   -0.05%     
  Complexity     7516     7516              
============================================
  Files          1020     1020              
  Lines         28831    28823       -8     
  Branches       2585     2580       -5     
============================================
- Hits          19678    19660      -18     
- Misses         7613     7624      +11     
+ Partials       1540     1539       -1     

Impacted Files	Coverage Δ
...henyu/loadbalancer/spi/LeastActiveLoadBalance.java	100.00% <100.00%> (+40.90%)	⬆️
...che/shenyu/sync/data/http/HttpSyncDataService.java	70.40% <0.00%> (-11.23%)	⬇️
...a/org/apache/shenyu/common/utils/VersionUtils.java	21.27% <0.00%> (-6.39%)	⬇️
...rg/apache/shenyu/plugin/rewrite/RewritePlugin.java	66.66% <0.00%> (-5.56%)	⬇️
...in/response/strategy/NettyClientMessageWriter.java	71.42% <0.00%> (-3.58%)	⬇️
...a/org/apache/shenyu/plugin/mock/util/MockUtil.java	77.55% <0.00%> (-2.05%)	⬇️
...yu/admin/service/impl/PluginHandleServiceImpl.java	74.07% <0.00%> (-1.86%)	⬇️
...client/brpc/BrpcContextRefreshedEventListener.java	68.57% <0.00%> (-1.43%)	⬇️
...henyu/common/cache/MemorySafeWindowTinyLFUMap.java	73.33% <0.00%> (ø)

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[damonxue]

pls review. @yu199195