Support spans that are split into multiple batches

[adinauer]

📜 Description

Invert isSpanTooOld check so spans that haven't been sent to Sentry yet survive until the next invocation of SpanExporter.export.

💡 Motivation and Context

When spans belonging to a single transaction were split into multiple batches for SpanExporter, we did not add all spans because the isSpanTooOld check wasn't inverted.

💚 How did you test it?

📝 Checklist

• I reviewed the submitted code.
• I added tests to verify the changes.
• No new PII added or SDK only sends newly added PII if sendDefaultPII is enabled.
• I updated the docs if needed.
• Review from the native team if needed.
• No breaking change or entry added to the changelog.
• No breaking change for hybrid SDKs or communicated to hybrid SDKs.

🔮 Next steps

[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	414.90 ms	466.55 ms	51.65 ms
Size	1.70 MiB	2.29 MiB	599.77 KiB

[lbloder]

LGTM 👍