[ISSUE #13297] Add build-helper-maven-plugin to support IDEA auto-recognize generated sources

[zhilu-tang]

What is the purpose of the change

Add build-helper-maven-plugin in root pom.xml to help IDEA automatically recognize generated source files under target/generated-sources directory, avoiding red squiggles in IDEA after source code import.

Brief changelog

• Add build-helper-maven-plugin configuration in root pom.xml to add generated sources directory

Verifying this change

1. Import project into IDEA
2. Verify that generated source files under target/generated-sources are properly recognized by IDEA
3. Verify no red squiggles appear for the generated source files

This change:

• is backwards-compatible
• is covered by tests
• affects documentation or requires documentation changes
• breaks KV-storage compatibility
• breaks HTTP API compatibility
• breaks CLI compatibility
• breaks Metrics compatibility

[github-actions]

Thanks for your this PR. 🙏
Please check again for your PR changes whether contains any usage/api/configuration change such as Add new API , Add new configuration, Change default value of configuration.
If so, please add or update documents(markdown type) in docs/next/ for repository nacos-group/nacos-group.github.io

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感谢您提交的PR。 🙏
请再次查看您的PR内容，确认是否包含任何使用方式/API/配置参数的变更，如：新增API、新增配置参数、修改默认配置等操作。
如果是，请确保在提交之前，在仓库nacos-group/nacos-group.github.io中的docs/next/目录下添加或更新文档（markdown格式）。

[CLAassistant]

All committers have signed the CLA.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 72.20%. Comparing base (bb7e34e) to head (76d5264).
Report is 219 commits behind head on develop.

Additional details and impacted files

@@              Coverage Diff              @@
##             develop   #13298      +/-   ##
=============================================
- Coverage      72.28%   72.20%   -0.08%     
+ Complexity     10063    10052      -11     
=============================================
  Files           1313     1313              
  Lines          42277    42277              
  Branches        4444     4444              
=============================================
- Hits           30560    30527      -33     
- Misses          9601     9623      +22     
- Partials        2116     2127      +11     

see 35 files with indirect coverage changes

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[wuyfee]

$\color{red}{FAILURE}$
DETAILS
✅ - docker: success
✅ - deploy (standalone & cluster & standalone_auth): success
✅ - e2e-java-test (standalone & cluster & standalone_auth): success
❌ - e2e-go-test (standalone & cluster): failure
✅ - e2e-cpp-test (standalone & cluster): success
✅ - e2e-csharp-test (standalone & cluster): success
✅ - e2e-nodejs-test (standalone & cluster): success
✅ - e2e-python-test (standalone & cluster): success
✅ - clean (standalone & cluster & standalone_auth): success