Create onCreate and onStart spans for all Activities

[stefanosiano]

📜 Description

ActivityLifecycleIntegration creates activity spans for all Activities, not only for appStart ones.

💡 Motivation and Context

We are currently adding onCreate and onStart spans only in the app start transaction. This PR will add these spans to all automatic transactions, too
Closes #2542

💚 How did you test it?

Unit test

📝 Checklist

• 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.
• I updated the wizard 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]

	Messages
📖	Do not forget to update Sentry-docs with your feature once the pull request gets approved.

Generated by 🚫 dangerJS against 4aecfa5

[stefanosiano]

Just a note:
In the app start transaction the spans are children of app.start.cold or app.start.warm span
For other Activities the spans are direct children of the parent transaction.

Also, this works for automatic transactions only. If we want to instrument custom transactions, we can easily use Sentry.getSpan instead of the transaction reference.
Any though on this?

[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	438.21 ms	454.28 ms	16.07 ms
Size	1.70 MiB	2.36 MiB	672.76 KiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
00c8eeb	415.32 ms	428.08 ms	12.76 ms

App size

Revision	Plain	With Sentry	Diff
00c8eeb	1.70 MiB	2.36 MiB	671.98 KiB