Export Span type for using startInactiveSpan

[lindboe]

📢 Type of change

• Bugfix
• New feature
• Enhancement
• Refactoring

📜 Description

Export the Span type so projects can use it.

💡 Motivation and Context

When working with startInactiveSpan, I've been writing some utilities to make managing spans easier across separate scopes (e.g., starting a span when a user clicks a button, and ending it when a loading spinner stops, which are in totally separate components. I'd also like to use this to make it easier to use withActiveSpan when I want.)

When doing this I noticed the type for Span was not exported, which I needed to type arguments for my utilities.

💚 How did you test it?

I made the same change in the project I'm working on.

📝 Checklist

• I added tests to verify changes
• No new PII added or SDK only sends newly added PII if sendDefaultPII is enabled
• I updated the docs if needed.
• I updated the wizard if needed.
• All tests passing
• No breaking changes

🔮 Next steps

Hopefully this one is straightforward and this is it 😄 let me know if you have any questions!

[antonis]

Thank you for your contribution @lindboe 🙇
The change looks good 🚀

Please consider adding an entry to the Unreleased section of CHANGELOG.md and we will be happy to merge your fix.

Example:

- Export `Span` type from `@sentry/types` ([#4345](https://github.com/getsentry/sentry-react-native/pull/4345))

[krystofwoldrich]

Thank you @lindboe for the contribution!