<fix>[thread]: guard Context.current() with telemetry check to prevent MN startup crash

[zstack-robot-2]

Resolves ZSTAC-82274. DispatchQueueImpl.SyncTaskFuture calls Context.current() unconditionally in constructor, triggering ServiceLoader for ContextStorageProvider even when telemetry is disabled. This causes ServiceConfigurationError when sentry-opentelemetry-bootstrap jar has ClassLoader conflicts in Tomcat.

sync from gitlab !9199

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

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概览

在 SyncTaskFuture 构造器中修改了 parentContext 的赋值逻辑，使其根据遥测启用状态进行条件判断：遥测启用时设为 Context.current()，否则设为 null。

变更

队列 / 文件	概述
条件逻辑优化 core/src/main/java/org/zstack/core/thread/DispatchQueueImpl.java	修改 SyncTaskFuture 构造器中 parentContext 的赋值，从无条件赋值改为根据遥测启用状态的条件赋值。

预估代码审查工作量

🎯 1 (微小) | ⏱️ ~3 分钟

诗

一只兔子来报信，
telemetry 状态要区分，
Context 现在更聪慧，
有无遥测各不同，
代码简洁又高效 🐰✨

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Important

Pre-merge checks failed

Please resolve all errors before merging. Addressing warnings is optional.

❌ Failed checks (1 error, 1 warning)

Check name	Status	Explanation	Resolution
Title check	❌ Error	PR title exceeds 72 character limit (87 chars) and does not meet the required format constraint, though it follows the type[scope]: description pattern.	缩短标题至72个字符以内。建议：'[thread]: Guard Context.current() with telemetry check' (59 characters)。
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description check	✅ Passed	The description clearly relates to the changeset, explaining the issue with Context.current() being called unconditionally and the telemetry-dependent fix.
Merge Conflict Detection	✅ Passed	✅ No merge conflicts detected when merging into 5.5.6

✨ 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/yaohua.wu/ZSTAC-82274

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