Fix spring-ai-1.x-plugin dropping the trace when stream() fails synchronously

[eye-gu]

Fix

• Add a unit test to verify that the fix works.
• Explain briefly why the bug exists and how to fix it.

• If this pull request closes/resolves/fixes an existing issue, replace the issue number. Closes [Bug] Spring AI streaming interceptor drops the whole trace segment when the stream call fails synchronously skywalking#14098.
• Update the CHANGES log.

[wu-sheng]

The fix seems to be good. could you update the changes.md?

[eye-gu]

The fix seems to be good. could you update the changes.md?

Thanks! Updated the CHANGES log.