fix: Finish TTID when viewWillAppear is skipped

[philipphofmann]

📜 Description

According to the Apple docs, viewWillAppear should be called before the UIViewController is added to the view hierarchy. There are some edge cases, though, when this doesn't happen, and we saw customers' transactions also proofing this. Therefore, we must also report the initial display here, as the customers' transactions had spans for viewWillLayoutSubViews.

💡 Motivation and Context

Fixes GH-4383

💚 How did you test it?

Unit tests

📝 Checklist

You have to check all boxes before merging:

• 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.

🔮 Next steps

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.321%. Comparing base (887502e) to head (518a25b).
Report is 6 commits behind head on main.

Additional details and impacted files

@@              Coverage Diff              @@
##              main     #4417       +/-   ##
=============================================
+ Coverage   91.303%   91.321%   +0.018%     
=============================================
  Files          609       609               
  Lines        49570     49630       +60     
  Branches     17857     17894       +37     
=============================================
+ Hits         45259     45323       +64     
+ Misses        4218      4216        -2     
+ Partials        93        91        -2     

Files with missing lines	Coverage Δ
.../Sentry/SentryUIViewControllerPerformanceTracker.m	99.086% <100.000%> (+0.008%)	⬆️
...entryUIViewControllerPerformanceTrackerTests.swift	98.404% <100.000%> (+0.179%)	⬆️

... and 6 files with indirect coverage changes

---

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[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	1219.51 ms	1226.81 ms	7.30 ms
Size	21.58 KiB	704.38 KiB	682.80 KiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
7cd187e	1239.39 ms	1258.02 ms	18.63 ms
5e66a38	1209.10 ms	1233.90 ms	24.79 ms
d760c3f	1200.95 ms	1233.96 ms	33.00 ms
324dc7b	1210.33 ms	1244.92 ms	34.59 ms
62c15d4	1231.80 ms	1248.86 ms	17.06 ms
9faf217	1268.86 ms	1274.82 ms	5.96 ms
39b1c35	1236.35 ms	1239.90 ms	3.55 ms
5d6ce0e	1237.10 ms	1257.46 ms	20.36 ms
5c115c5	1249.04 ms	1260.36 ms	11.32 ms
50bb751	1230.94 ms	1238.69 ms	7.75 ms

App size

Revision	Plain	With Sentry	Diff
7cd187e	20.76 KiB	401.65 KiB	380.89 KiB
5e66a38	22.85 KiB	408.88 KiB	386.03 KiB
d760c3f	22.84 KiB	403.17 KiB	380.33 KiB
324dc7b	22.85 KiB	408.84 KiB	385.99 KiB
62c15d4	22.85 KiB	411.14 KiB	388.29 KiB
9faf217	20.76 KiB	419.70 KiB	398.94 KiB
39b1c35	22.85 KiB	408.88 KiB	386.03 KiB
5d6ce0e	22.85 KiB	405.38 KiB	382.53 KiB
5c115c5	22.85 KiB	411.72 KiB	388.87 KiB
50bb751	21.58 KiB	417.86 KiB	396.27 KiB

[brustolin]

I have one suggestion, but it looks good to me