Adjust ElasticSearch index refresh period as INT(flushInterval * 2/3)

[wu-sheng]

• If this pull request closes/resolves/fixes an existing issue, replace the issue number. Closes #.
• Update the CHANGES log.

Adjust index refresh period as INT(flushInterval * 2/3), it used to be as same as bulk flush period. At the edge case, in low traffic(traffic < bulkActions in the whole period), there is a possible case, 2 period bulks are included in one index refresh rebuild operation, which could cause version conflicts. And this case can't be fixed through core/persistentPeriod as the bulk fresh is not controlled by the persistent timer anymore.

This PR should avoid the following exception in the low load case, especially when bulkActions is set larger than the number of a metric type.

[codecov]

Codecov Report

Merging #7310 (dc56d4f) into master (408bbf8) will decrease coverage by 14.73%.
The diff coverage is 50.00%.

❗ Current head dc56d4f differs from pull request most recent head 663a8bd. Consider uploading reports for the commit 663a8bd to get more accurate results

@@              Coverage Diff              @@
##             master    #7310       +/-   ##
=============================================
- Coverage     59.03%   44.29%   -14.74%     
+ Complexity     4373     2747     -1626     
=============================================
  Files          1027     1890      +863     
  Lines         26449    40598    +14149     
  Branches       2618     4749     +2131     
=============================================
+ Hits          15614    17983     +2369     
- Misses         9457    21508    +12051     
+ Partials       1378     1107      -271     

Impacted Files	Coverage Δ
...lasticsearch/StorageModuleElasticsearchConfig.java	100.00% <ø> (ø)
.../plugin/elasticsearch/base/StorageEsInstaller.java	79.67% <50.00%> (-2.00%)	⬇️
...skywalking/oap/server/core/alarm/AlarmMessage.java	0.00% <0.00%> (-100.00%)	⬇️
...ywalking/apm/agent/core/plugin/EnhanceContext.java	0.00% <0.00%> (-100.00%)	⬇️
...walking/apm/agent/core/plugin/match/NameMatch.java	0.00% <0.00%> (-100.00%)	⬇️
...ing/oap/server/core/storage/IHistoryDeleteDAO.java	0.00% <0.00%> (-100.00%)	⬇️
...ng/oap/server/core/analysis/config/NoneStream.java	0.00% <0.00%> (-100.00%)	⬇️
...log/analyzer/provider/log/ILogAnalyzerService.java	0.00% <0.00%> (-100.00%)	⬇️
...ement/ui/template/UITemplateManagementService.java	0.00% <0.00%> (-100.00%)	⬇️
...gin/interceptor/enhance/MethodInterceptResult.java	0.00% <0.00%> (-100.00%)	⬇️
... and 1455 more

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