fix(appStart): Add frame delay data in app start span

[antonis]

Based on: #4865

📢 Type of change

• Bugfix
• New feature
• Enhancement
• Refactoring

📜 Description

💡 Motivation and Context

Fixes #4869

💚 How did you test it?

📝 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

[github-actions]

	Fails
🚫	Please consider adding a changelog entry for the next release.

Instructions and example for changelog

Please add an entry to CHANGELOG.md to the "Unreleased" section. Make sure the entry includes this PR's number.

Example:

## Unreleased

- Add frame delay data in app start span ([#4873](https://github.com/getsentry/sentry-react-native/pull/4873))

If none of the above apply, you can opt out of this check by adding #skip-changelog to the PR description.

Generated by 🚫 dangerJS against 00c0c03

[github-actions]

Android (new) Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	429.29 ms	436.42 ms	7.13 ms
Size	7.15 MiB	8.42 MiB	1.26 MiB

Baseline results on branch: antonis/appstart-frames

Startup times

Revision	Plain	With Sentry	Diff
11da461+dirty	413.22 ms	438.36 ms	25.14 ms
2d71b61+dirty	406.57 ms	393.79 ms	-12.78 ms

App size

Revision	Plain	With Sentry	Diff
11da461+dirty	7.15 MiB	8.42 MiB	1.26 MiB
2d71b61+dirty	7.15 MiB	8.42 MiB	1.26 MiB