refactor: Add null unwrapping to silence handled nullability warnings

[philprime]

This PR is derived from #5572 in an effort to make the large amount of changes easier to review for #5577.

This PR must be merged after #5777

Adds the macro SENTRY_UNWRAP_NULLABLE for already handled cases to silence warnings

#skip-changelog

[codecov]

❌ 3 Tests Failed:

Tests completed	Failed	Passed	Skipped
31827	3	31824	97

View the top 2 failed test(s) by shortest run time

SentryTests.SentrySDKInternalTests::testResumeAndPauseAppHangTracking

Stack Traces | 0s run time

.../Tests/SentryTests/SentrySDKInternalTests.swift:579 - XCTAssertEqual failed: ("1") is not equal to ("0")

iOS_Swift6_UITests.UITests::testLaunchAndCaptureError

Stack Traces | 0s run time

.../iOS-Swift6/iOS-Swift6-UITests/UITests.swift:11 - Failed to get background assertion for target app with pid 6840: Timed out while acquiring background assertion.

View the full list of 1 ❄️ flaky tests

iOS_SwiftUI_UITests.FeedbackUITests::testWidgetDisplayInSwiftUIApp

Flake rate in main: 23.81% (Passed 16 times, Failed 5 times)

Stack Traces | 0s run time

.../iOS-SwiftUI/iOS-SwiftUI-UITests/FeedbackUITests.swift:14 - Failed to get matching snapshots: Timed out while evaluating UI query.

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[philipphofmann]

LGTM, when not making these defines public in SentryDefines.h

[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	1228.37 ms	1251.34 ms	22.97 ms
Size	23.74 KiB	913.74 KiB	890.00 KiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
4e3915a	1230.02 ms	1258.90 ms	28.88 ms
c2982e7	1223.92 ms	1242.86 ms	18.94 ms
736bcfb	1229.86 ms	1249.59 ms	19.73 ms
2a07609	1207.79 ms	1233.77 ms	25.98 ms
9add417	1224.33 ms	1243.06 ms	18.73 ms
2a7868a	1226.54 ms	1256.92 ms	30.37 ms
d38165b	1211.41 ms	1242.49 ms	31.08 ms
42cfd79	1222.13 ms	1244.23 ms	22.10 ms
aa98fe8	1227.69 ms	1253.18 ms	25.50 ms
b714cb9	1224.71 ms	1238.04 ms	13.33 ms

App size

Revision	Plain	With Sentry	Diff
4e3915a	23.75 KiB	858.69 KiB	834.94 KiB
c2982e7	23.75 KiB	911.62 KiB	887.87 KiB
736bcfb	23.74 KiB	891.02 KiB	867.28 KiB
2a07609	23.75 KiB	912.78 KiB	889.03 KiB
9add417	23.75 KiB	908.40 KiB	884.65 KiB
2a7868a	23.75 KiB	880.20 KiB	856.45 KiB
d38165b	23.75 KiB	855.37 KiB	831.62 KiB
42cfd79	23.75 KiB	880.20 KiB	856.45 KiB
aa98fe8	23.75 KiB	891.01 KiB	867.26 KiB
b714cb9	23.75 KiB	858.69 KiB	834.93 KiB

Previous results on branch: philprime/strict-nullability-6

Startup times

Revision	Plain	With Sentry	Diff
a6679b1	1210.02 ms	1237.24 ms	27.22 ms
17eb25b	1221.06 ms	1231.31 ms	10.24 ms
3af5b54	1219.20 ms	1241.34 ms	22.14 ms
3a0db03	1209.72 ms	1240.47 ms	30.75 ms
f9e69b3	1232.48 ms	1264.38 ms	31.90 ms

App size

Revision	Plain	With Sentry	Diff
a6679b1	23.75 KiB	913.50 KiB	889.75 KiB
17eb25b	23.75 KiB	912.97 KiB	889.22 KiB
3af5b54	23.75 KiB	912.97 KiB	889.23 KiB
3a0db03	23.75 KiB	912.57 KiB	888.82 KiB
f9e69b3	23.75 KiB	913.50 KiB	889.75 KiB