perf(modules): Pre-load modules on a background thread

[romtsn]

📜 Description

• Pre-load modules on a background thread upon initialization so we don't need to load them when an error/crash happens (could be on the main thread)
• Fix cachedModules were not thread-safe

💡 Motivation and Context

An actual ANR from GPC originating in UncaughtExceptionHandler
https://play.google.com/sdk-console/accounts/3062283563667932501/sdks/5766124106675877123/crashes/44125318/details

💚 How did you test it?

Manually + existing tests

📝 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]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	421.51 ms	470.70 ms	49.19 ms
Size	1.58 MiB	2.08 MiB	507.33 KiB

Previous results on branch: rz/perf/modules-preload

Startup times

Revision	Plain	With Sentry	Diff
7b2ad27	404.76 ms	444.04 ms	39.29 ms

App size

Revision	Plain	With Sentry	Diff
7b2ad27	1.58 MiB	2.08 MiB	507.38 KiB