fix: Crash in CppException Monitor

[philipphofmann]

📜 Description

Only call the previous terminate_handler if it's not NULL to avoid crashing.

💡 Motivation and Context

Fixes #1533

💚 How did you test it?

Unit test.

📝 Checklist

• I reviewed the submitted code
• I added tests to verify the changes
• I updated the docs if needed
• Review from the native team if needed
• No breaking changes

🔮 Next steps

[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	1198.92 ms	1226.70 ms	27.78 ms
Size	20.76 KiB	419.70 KiB	398.94 KiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
feba2be	1246.67 ms	1254.64 ms	7.97 ms
302ee8b	1194.02 ms	1223.34 ms	29.32 ms
dc0db9e	1246.06 ms	1260.46 ms	14.40 ms
b2f82fa	1236.94 ms	1262.86 ms	25.92 ms
5cabf7e	1247.12 ms	1249.61 ms	2.49 ms
dc0db9e	1222.10 ms	1240.90 ms	18.80 ms
7fb7afb	1227.73 ms	1243.16 ms	15.43 ms
b2f82fa	1237.78 ms	1256.02 ms	18.24 ms
3f1be0f	1208.12 ms	1225.72 ms	17.60 ms
56ec5d0	1194.39 ms	1236.94 ms	42.55 ms

App size

Revision	Plain	With Sentry	Diff
feba2be	20.76 KiB	414.45 KiB	393.69 KiB
302ee8b	20.76 KiB	419.62 KiB	398.87 KiB
dc0db9e	20.76 KiB	419.62 KiB	398.86 KiB
b2f82fa	20.76 KiB	419.62 KiB	398.86 KiB
5cabf7e	20.76 KiB	419.67 KiB	398.91 KiB
dc0db9e	20.76 KiB	419.62 KiB	398.86 KiB
7fb7afb	20.76 KiB	419.70 KiB	398.94 KiB
b2f82fa	20.76 KiB	419.62 KiB	398.86 KiB
3f1be0f	20.76 KiB	414.44 KiB	393.69 KiB
56ec5d0	20.76 KiB	414.44 KiB	393.68 KiB

Previous results on branch: fix/crash-in-cpp-exception-monitor

Startup times

Revision	Plain	With Sentry	Diff
0c81643	1242.18 ms	1258.49 ms	16.31 ms

App size

Revision	Plain	With Sentry	Diff
0c81643	20.76 KiB	419.70 KiB	398.94 KiB

[armcknight]

LGTM, and thanks for including the link to the docs explaining the situation 👍🏻