fix(test): Fix flaky MainEventProcessorTest by checking crashed thread

[adinauer]

#skip-changelog

📜 Description

Fix MainEventProcessorTest to assert the stacktrace on the crashed thread (isCrashed == true) instead of the first thread in the list. Thread ordering is non-deterministic, so first() may return a non-crashed thread causing the test to flake.

💡 Motivation and Context

This test was flaky due to the new SentryOptions.activate changes affecting thread ordering. The fix ensures we find the correct crashed thread before asserting on its stacktrace.

💚 How did you test it?

Verified the previously flaky test now passes consistently.

📝 Checklist

• No new PII added or SDK only sends newly added PII if sendDefaultPII is enabled.
• No breaking change or entry added to the changelog.
• No breaking change for hybrid SDKs or communicated to hybrid SDKs.

🔮 Next steps

None.

[github-actions]

Semver Impact of This PR

🟢 Patch (bug fixes)

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[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	306.71 ms	355.49 ms	48.78 ms
Size	1.58 MiB	2.29 MiB	720.88 KiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
e59e22a	329.74 ms	383.31 ms	53.57 ms
fc5ccaf	270.49 ms	363.90 ms	93.41 ms
d15471f	361.89 ms	378.07 ms	16.18 ms
d15471f	322.58 ms	396.08 ms	73.50 ms
abfcc92	304.04 ms	370.33 ms	66.29 ms
91bb874	310.68 ms	359.24 ms	48.56 ms
ab8a72d	316.24 ms	356.38 ms	40.14 ms
d15471f	286.65 ms	314.68 ms	28.03 ms
6727e14	337.22 ms	373.94 ms	36.71 ms
f064536	329.00 ms	395.62 ms	66.62 ms

App size

Revision	Plain	With Sentry	Diff
e59e22a	1.58 MiB	2.20 MiB	635.34 KiB
fc5ccaf	1.58 MiB	2.13 MiB	557.54 KiB
d15471f	1.58 MiB	2.13 MiB	559.54 KiB
d15471f	1.58 MiB	2.13 MiB	559.54 KiB
abfcc92	1.58 MiB	2.13 MiB	557.31 KiB
91bb874	1.58 MiB	2.13 MiB	559.07 KiB
ab8a72d	1.58 MiB	2.12 MiB	551.55 KiB
d15471f	1.58 MiB	2.13 MiB	559.54 KiB
6727e14	1.58 MiB	2.28 MiB	718.64 KiB
f064536	1.58 MiB	2.20 MiB	633.90 KiB

Previous results on branch: fix/flaky-test-main-event-processor

Startup times

Revision	Plain	With Sentry	Diff
b7f9745	306.38 ms	352.51 ms	46.13 ms

App size

Revision	Plain	With Sentry	Diff
b7f9745	1.58 MiB	2.29 MiB	720.89 KiB