Warm starts cleanup

[stefanosiano]

📜 Description

• moved activity lifecycle spans logic into a separate class ActivityLifecycleSpanHelper
• moved processInitSpan creation to AppStartMetrics
• ActivityLifecycleIntegration now create regular spans, and adds TimeSpans to AppStartMetrics to handle hybrid SDKs
• PerformanceAndroidEventProcessor does not add activity lifecycle spans to the transaction, as they are added by ActivityLifecycleIntegration directly
• removed activity callback from SentryPerformanceProvider

💡 Motivation and Context

Cleans some code after the warm start changes
I added a separate PR to avoid having too many logical changes in one

💚 How did you test it?

📝 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]

	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

- Warm starts cleanup ([#3954](https://github.com/getsentry/sentry-java/pull/3954))

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 d0764bd

[github-actions]

🚨 Detected changes in high risk code 🚨

High-risk code has higher potential to break the SDK and may be hard to test. To prevent severe bugs, apply the rollout process for releasing such changes and be extra careful when changing and reviewing these files:

• sentry-android-core/src/main/java/io/sentry/android/core/InternalSentrySdk.java

[github-actions]

🚨 Detected changes in high risk code 🚨

High-risk code has higher potential to break the SDK and may be hard to test. To prevent severe bugs, apply the rollout process for releasing such changes and be extra careful when changing and reviewing these files:

• sentry-android-core/src/main/java/io/sentry/android/core/InternalSentrySdk.java

[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	419.41 ms	429.41 ms	10.00 ms
Size	1.70 MiB	2.36 MiB	669.84 KiB

Baseline results on branch: fix/warm-starts

Startup times

Revision	Plain	With Sentry	Diff
c21a34f	369.28 ms	441.12 ms	71.84 ms
34c4186	410.50 ms	437.28 ms	26.78 ms

App size

Revision	Plain	With Sentry	Diff
c21a34f	1.70 MiB	2.36 MiB	669.76 KiB
34c4186	1.70 MiB	2.36 MiB	669.76 KiB

Previous results on branch: fix/warm-starts-cleanup

Startup times

Revision	Plain	With Sentry	Diff
3c20f24	404.14 ms	488.88 ms	84.74 ms

App size

Revision	Plain	With Sentry	Diff
3c20f24	1.70 MiB	2.36 MiB	669.84 KiB

[github-actions]

🚨 Detected changes in high risk code 🚨

High-risk code has higher potential to break the SDK and may be hard to test. To prevent severe bugs, apply the rollout process for releasing such changes and be extra careful when changing and reviewing these files:

• sentry-android-core/src/main/java/io/sentry/android/core/InternalSentrySdk.java