Fix UncaughtExceptionHandlerIntegration Memory Leak

[lbloder]

Upon registration check if an UncaughtExceptionHandlerIntegration is already set as defaultUncaughtExceptionHandler, if so, set its defaultExceptionHandler as the default of the new UncaughtExceptionHandlerIntegration.

:bulb: Motivation and Context

Fixes #3266

:green_heart: How did you test it?

:pencil: Checklist

• [ ] I reviewed the submitted code.
• [ ] 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.
• [ ] 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.

:crystal_ball: Next steps

[github-actions[bot]]

Performance metrics :rocket:

	Plain	With Sentry	Diff
Startup time	372.02 ms	439.62 ms	67.60 ms
Size	1.70 MiB	2.28 MiB	592.99 KiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
baaf6371cb120f45ad4fed59e8b97e65e3381cfd	462.32 ms	579.22 ms	116.90 ms
28c9a83af55b119517dbd2fcf74975fb5822907b	416.98 ms	479.90 ms	62.92 ms
201048a0cf146f24a001d1c7997aae2ef84b23c3	418.62 ms	481.67 ms	63.05 ms
7ab32b6ab8bc72b973328a00840eb192b151b59f	373.62 ms	480.61 ms	106.99 ms
b172d4ed57bfa46dfac6bee0216bea7d0126b253	352.92 ms	446.50 ms	93.58 ms
3d8bd2ba0c81c9aa6084fa222f9a7706cf5e8d92	364.76 ms	469.98 ms	105.22 ms
1e05e43aac4e7f22213e0ec71fa5a89a74588c91	411.00 ms	467.29 ms	56.29 ms
c554ca260c5f0fa79a30d592f6c0e08a850a5014	383.78 ms	449.84 ms	66.06 ms
0bd723b1c59af639c4a86bbade526e0108096f8e	375.20 ms	452.41 ms	77.20 ms
99a51e2957c3044db1b481b67e733b42ee267926	405.11 ms	479.65 ms	74.54 ms

App size

Revision	Plain	With Sentry	Diff
baaf6371cb120f45ad4fed59e8b97e65e3381cfd	1.72 MiB	2.27 MiB	558.42 KiB
28c9a83af55b119517dbd2fcf74975fb5822907b	1.70 MiB	2.28 MiB	592.00 KiB
201048a0cf146f24a001d1c7997aae2ef84b23c3	1.70 MiB	2.28 MiB	592.32 KiB
7ab32b6ab8bc72b973328a00840eb192b151b59f	1.70 MiB	2.27 MiB	584.63 KiB
b172d4ed57bfa46dfac6bee0216bea7d0126b253	1.72 MiB	2.29 MiB	578.09 KiB
3d8bd2ba0c81c9aa6084fa222f9a7706cf5e8d92	1.72 MiB	2.29 MiB	577.53 KiB
1e05e43aac4e7f22213e0ec71fa5a89a74588c91	1.70 MiB	2.28 MiB	590.89 KiB
c554ca260c5f0fa79a30d592f6c0e08a850a5014	1.70 MiB	2.27 MiB	582.25 KiB
0bd723b1c59af639c4a86bbade526e0108096f8e	1.72 MiB	2.29 MiB	578.09 KiB
99a51e2957c3044db1b481b67e733b42ee267926	1.72 MiB	2.29 MiB	576.34 KiB