fix: Crash when user feedback block is nil

[noahsmartin]

If you had done options.configureUserFeedback = nil the app would crash, this fixes it

Closes #6643

[codecov]

Codecov Report

❌ Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (main@17a26bf). Learn more about missing BASE report.
⚠️ Report is 6 commits behind head on main.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
Sources/Sentry/SentryOptions.m	0.000%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##             main     #6642   +/-   ##
========================================
  Coverage        ?   85.171%           
========================================
  Files           ?       452           
  Lines           ?     27669           
  Branches        ?     12116           
========================================
  Hits            ?     23566           
  Misses          ?      4059           
  Partials        ?        44           

Files with missing lines	Coverage Δ
Sources/Sentry/SentryOptions.m	95.882% <0.000%> (ø)

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[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	1207.62 ms	1242.31 ms	34.69 ms
Size	23.75 KiB	1023.81 KiB	1000.06 KiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
995b436	1217.54 ms	1254.26 ms	36.72 ms
f37e3fe	1230.24 ms	1254.51 ms	24.27 ms
0ac4c65	1236.85 ms	1267.84 ms	30.98 ms
339539a	1219.58 ms	1254.63 ms	35.05 ms
ebc3a34	1236.24 ms	1261.02 ms	24.78 ms
781f560	1232.83 ms	1263.56 ms	30.73 ms
e98d6f5	1228.51 ms	1258.85 ms	30.34 ms
b709887	1193.52 ms	1216.74 ms	23.22 ms
37183fe	1212.33 ms	1238.92 ms	26.59 ms
3279d4e	1215.76 ms	1256.45 ms	40.69 ms

App size

Revision	Plain	With Sentry	Diff
995b436	23.75 KiB	1.02 MiB	1016.76 KiB
f37e3fe	23.75 KiB	919.70 KiB	895.95 KiB
0ac4c65	23.75 KiB	968.24 KiB	944.50 KiB
339539a	23.75 KiB	968.24 KiB	944.50 KiB
ebc3a34	23.75 KiB	919.91 KiB	896.16 KiB
781f560	23.75 KiB	1.02 MiB	1016.46 KiB
e98d6f5	23.75 KiB	933.03 KiB	909.28 KiB
b709887	23.75 KiB	1.01 MiB	1016.14 KiB
37183fe	23.75 KiB	913.63 KiB	889.87 KiB
3279d4e	23.75 KiB	938.32 KiB	914.57 KiB

[philprime]

LGTM, thank you for finding this!