<fix>[volumebackup]: add backup cancel timeout error code

[MatheMatrix]

Summary

Add ORG_ZSTACK_STORAGE_BACKUP_CANCEL_TIMEOUT constant to CloudOperationsErrorCode for use by premium volumebackup module.

This is the @@2 companion MR for premium MR !12975 which adds a backup chain task exit wait mechanism after cancel.

Resolves: ZSTAC-82195
Target: 5.5.12

sync from gitlab !9200

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

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总结

向 CloudOperationsErrorCode 类添加了新的静态常量 ORG_ZSTACK_STORAGE_BACKUP_CANCEL_TIMEOUT，用于表示存储备份取消超时的错误代码。

变更内容

内聚/文件	总结
存储备份错误代码 utils/src/main/java/org/zstack/utils/clouderrorcode/CloudOperationsErrorCode.java	添加新的静态常量 ORG_ZSTACK_STORAGE_BACKUP_CANCEL_TIMEOUT，位置紧邻现有的存储备份错误代码块，遵循已有的命名和值规范。

代码审查工作量评估

🎯 1 (微小) | ⏱️ ~2 分钟

诗歌

🐰 一行新代码悄然而至，
错误代码库又添新兵，
备份超时不再困扰我，
常量清晰，逻辑分明，
简洁优雅，就是这样！ ✨

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	PR标题遵循了指定的格式要求，包含了[scope]: description>的结构，长度为57个字符（在72字符限制内），并且准确描述了PR的主要变更。
Description check	✅ Passed	PR描述清晰相关，说明了添加新常量的目的、关联的premium MR以及相关的JIRA问题，与变更集内容保持一致。
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Merge Conflict Detection	✅ Passed	✅ No merge conflicts detected when merging into 5.5.12

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch sync/ye.zou/fix/ZSTAC-82195

Warning

There were issues while running some tools. Please review the errors and either fix the tool's configuration or disable the tool if it's a critical failure.

🔧 ast-grep (0.40.5)

utils/src/main/java/org/zstack/utils/clouderrorcode/CloudOperationsErrorCode.java

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