feat: Report start up crashes

[philipphofmann]

📜 Description

If the app crashes after 2 seconds of the SDK init, the SDK makes the SDK init call blocking
by calling flush with 5 seconds.

💡 Motivation and Context

Fixes GH-316 also tracked in getsentry/team-mobile#12.

💚 How did you test it?

Unit tests, and real devices.

📝 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]

	Messages
📖	Do not forget to update Sentry-docs with your feature once the pull request gets approved.

Generated by 🚫 dangerJS against 1e23bc6

[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	1223.14 ms	1243.84 ms	20.70 ms
Size	20.51 KiB	332.59 KiB	312.09 KiB

Baseline results on branch: master

Startup times

Revision	Plain	With Sentry	Diff
7138b7d	1243.40 ms	1252.08 ms	8.68 ms
864c39a	1226.12 ms	1248.26 ms	22.13 ms
202334c	1265.41 ms	1277.34 ms	11.93 ms
074350f	1241.00 ms	1249.60 ms	8.60 ms
4a66f00	1224.73 ms	1241.14 ms	16.41 ms
864c39a	1191.14 ms	1233.38 ms	42.24 ms
172c95a	1220.08 ms	1251.74 ms	31.66 ms
9fc2dd0	1246.14 ms	1275.00 ms	28.86 ms
791123d	1256.10 ms	1266.68 ms	10.58 ms
4a66f00	1259.84 ms	1281.66 ms	21.82 ms

App size

Revision	Plain	With Sentry	Diff
7138b7d	20.51 KiB	331.79 KiB	311.28 KiB
864c39a	20.51 KiB	335.57 KiB	315.06 KiB
202334c	20.51 KiB	331.79 KiB	311.28 KiB
074350f	20.51 KiB	335.52 KiB	315.01 KiB
4a66f00	20.51 KiB	331.79 KiB	311.28 KiB
864c39a	20.51 KiB	335.57 KiB	315.06 KiB
172c95a	20.51 KiB	335.57 KiB	315.06 KiB
9fc2dd0	20.50 KiB	331.79 KiB	311.28 KiB
791123d	20.51 KiB	331.81 KiB	311.30 KiB
4a66f00	20.51 KiB	331.79 KiB	311.28 KiB

Previous results on branch: feat/detect-start-up-crashes

Startup times

Revision	Plain	With Sentry	Diff
5308b1e	1236.73 ms	1244.10 ms	7.37 ms
f03289c	1227.66 ms	1242.80 ms	15.14 ms
53ede48	1236.90 ms	1255.30 ms	18.40 ms
03e9d9d	1224.94 ms	1238.77 ms	13.83 ms
88ce892	1229.32 ms	1250.67 ms	21.35 ms
ab75e0c	1223.40 ms	1264.40 ms	41.00 ms

App size

Revision	Plain	With Sentry	Diff
5308b1e	20.51 KiB	332.54 KiB	312.03 KiB
f03289c	20.51 KiB	332.59 KiB	312.08 KiB
53ede48	20.51 KiB	332.48 KiB	311.98 KiB
03e9d9d	20.51 KiB	335.69 KiB	315.19 KiB
88ce892	20.51 KiB	332.47 KiB	311.96 KiB
ab75e0c	20.51 KiB	335.69 KiB	315.18 KiB

[brustolin]

LGTM