fix: Free memory returned by backtrace_symbols() in debug builds

[indragiek]

📜 Description

This code is only compiled in debug builds, but we were forgetting to free the pointer returned by backtrace_symbols. The documentation (https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man3/backtrace_symbols.3.html) says:

It is allocated using malloc() and should be released using free()

💡 Motivation and Context

Customer reported a memory leak in a call to backtrace_symbols, this is the cause.

💚 How did you test it?

Verify that the memory is freed and does not leak in a debug build.

📝 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

Merging #3202 (2f5905e) into main (25e65a5) will decrease coverage by 0.051%.
The diff coverage is 100.000%.

Additional details and impacted files

@@              Coverage Diff              @@
##              main     #3202       +/-   ##
=============================================
- Coverage   89.190%   89.139%   -0.051%     
=============================================
  Files          502       502               
  Lines        54034     54022       -12     
  Branches     19386     19376       -10     
=============================================
- Hits         48193     48155       -38     
- Misses        4988      5008       +20     
- Partials       853       859        +6     

Files Changed	Coverage Δ
Sources/Sentry/Profiling/SentryProfilerState.mm	98.425% <100.000%> (+0.038%)	⬆️

... and 13 files with indirect coverage changes

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[bruno-garcia]

Checks out, only usage of that is under DEBUG builds.

[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	1235.61 ms	1253.64 ms	18.03 ms
Size	22.84 KiB	403.19 KiB	380.34 KiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
cbf6225	1221.73 ms	1251.20 ms	29.47 ms
bd2afa6	1245.24 ms	1263.18 ms	17.94 ms
11ccc16	1206.45 ms	1225.60 ms	19.15 ms
28333b6	1247.29 ms	1262.51 ms	15.22 ms
ff5c1d8	1244.30 ms	1263.96 ms	19.66 ms
4654f66	1247.16 ms	1263.96 ms	16.80 ms
3f366ee	1242.28 ms	1260.80 ms	18.52 ms
67460f4	1244.56 ms	1255.96 ms	11.40 ms
8f397a7	1236.76 ms	1256.76 ms	20.00 ms
1bf8571	1215.31 ms	1232.48 ms	17.17 ms

App size

Revision	Plain	With Sentry	Diff
cbf6225	20.76 KiB	425.77 KiB	405.00 KiB
bd2afa6	20.76 KiB	420.55 KiB	399.79 KiB
11ccc16	20.76 KiB	431.71 KiB	410.94 KiB
28333b6	20.76 KiB	424.69 KiB	403.93 KiB
ff5c1d8	20.76 KiB	430.98 KiB	410.22 KiB
4654f66	20.76 KiB	432.17 KiB	411.41 KiB
3f366ee	20.76 KiB	427.84 KiB	407.08 KiB
67460f4	20.76 KiB	426.15 KiB	405.39 KiB
8f397a7	20.76 KiB	420.55 KiB	399.79 KiB
1bf8571	20.76 KiB	437.12 KiB	416.36 KiB

Previous results on branch: indragiek/free-backtrace-symbols

Startup times

Revision	Plain	With Sentry	Diff
78fc65a	1232.78 ms	1242.96 ms	10.18 ms

App size

Revision	Plain	With Sentry	Diff
78fc65a	22.84 KiB	403.19 KiB	380.34 KiB