fix(ios): honor _experiments.enableUnhandledCPPExceptionsV2 on v8

[antonis]

Note

Stacked on #6012. Review/merge that one first; once it lands, rebase this onto main.

📢 Type of change

• Bugfix

📜 Description

Same dead-code drift as the profiling fix in #6012. SentrySDKWrapper.createOptionsWithDictionary parses _experiments.enableUnhandledCPPExceptionsV2 into sentryOptions.experimental.enableUnhandledCPPExceptionsV2 (ios/SentrySDKWrapper.m:105-108), but SentrySDKWrapper has not been on the live init path since #5582 moved init to RNSentryStart. So on iOS this option has been silently ignored in every 8.x release — user Sentry.init({ _experiments: { enableUnhandledCPPExceptionsV2: true } }) does not reach Cocoa.

(Verified Cocoa's SentryOptionsInternal.m does not auto-map _experiments.* from the raw dictionary — only top-level keys like enableLogs. So the gap is real.)

This PR extends the _experiments block introduced in #6012 to also port enableUnhandledCPPExceptionsV2 handling. Adds enabled / disabled / default XCTest coverage on RNSentryStart, mirroring the coverage SentrySDKWrapper already had but on the live path.

💡 Motivation and Context

User-facing: with enableUnhandledCPPExceptionsV2: true set in JS, iOS still falls back to the default handler, so C++ crashes don't get the more reliable __cxa_throw hooking. Same class of silent drop as the profiling regression — same fix pattern.

💚 How did you test it?

• Three new XCTest cases on RNSentryStart:
  • testStartCreateOptionsWithDictionaryEnableUnhandledCPPExceptionsV2Enabled → asserts actualOptions.experimental.enableUnhandledCPPExceptionsV2 == YES
  • …Disabled → asserts == NO
  • …Default (no _experiments key) → asserts == NO
• Locally: yarn build, yarn circularDepCheck, ./scripts/clang-format.sh lint all clean.

📝 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]

Semver Impact of This PR

⚪ None (no version bump detected)

📋 Changelog Preview

This is how your changes will appear in the changelog.
Entries from this PR are highlighted with a left border (blockquote style).

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• fix(ios): honor _experiments.enableUnhandledCPPExceptionsV2 on v8 by antonis in #6014

• chore(deps): update JavaScript SDK to v10.49.0 by github-actions in #6011
• fix(profiling): iOS UI profiling on v8 by antonis in #6012
• ci: Integrate Warden for AI-powered PR code review by antonis in #6003
• chore(lint): Fixes lint issue on main by antonis in #6013
• feat(expo): Warn when prebuilt native projects are missing Sentry config by alwx in #5984

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_{🤖 This preview updates automatically when you update the PR.}

[sentry]

📲 Install Builds

Android

🔗 App Name	App ID	Version	Configuration
Sentry RN	io.sentry.reactnative.sample	8.8.0 (83)	Release

⚙️ sentry-react-native Build Distribution Settings

[github-actions]

iOS (legacy) Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	1247.35 ms	1233.88 ms	-13.47 ms
Size	3.38 MiB	4.76 MiB	1.38 MiB

[github-actions]

iOS (new) Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	1217.37 ms	1221.53 ms	4.16 ms
Size	3.38 MiB	4.76 MiB	1.38 MiB