fix: Don't override sentry-trace and baggage headers

[brustolin]

📜 Description

Don't override sentry-trace and baggage headers in a http request.
Cross platform SDKs may set this headers and we're overriding it.

💡 Motivation and Context

Close #3490

💚 How did you test it?

Unit test

📝 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

[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	1212.18 ms	1225.35 ms	13.17 ms
Size	21.58 KiB	418.86 KiB	397.28 KiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
a6ac3d2	1219.00 ms	1231.32 ms	12.32 ms
60dd0f5	1238.98 ms	1254.48 ms	15.50 ms
e89dc54	1220.57 ms	1233.45 ms	12.88 ms
d9fff0f	1205.09 ms	1247.40 ms	42.31 ms
734d507	1201.78 ms	1213.96 ms	12.18 ms
98cca71	1230.43 ms	1252.36 ms	21.93 ms
cd39d58	1203.87 ms	1239.88 ms	36.01 ms
c6773e5	1222.48 ms	1240.02 ms	17.54 ms
c319795	1205.12 ms	1231.20 ms	26.08 ms
75ef4eb	1237.30 ms	1249.53 ms	12.23 ms

App size

Revision	Plain	With Sentry	Diff
a6ac3d2	20.76 KiB	436.65 KiB	415.89 KiB
60dd0f5	20.76 KiB	393.37 KiB	372.61 KiB
e89dc54	22.85 KiB	412.60 KiB	389.75 KiB
d9fff0f	22.85 KiB	401.65 KiB	378.81 KiB
734d507	22.85 KiB	412.66 KiB	389.81 KiB
98cca71	22.85 KiB	411.14 KiB	388.29 KiB
cd39d58	20.76 KiB	435.26 KiB	414.50 KiB
c6773e5	20.76 KiB	435.25 KiB	414.49 KiB
c319795	20.76 KiB	431.99 KiB	411.22 KiB
75ef4eb	22.85 KiB	413.45 KiB	390.60 KiB

Previous results on branch: fix/trace-header

Startup times

Revision	Plain	With Sentry	Diff
28a6968	1204.69 ms	1220.02 ms	15.33 ms
6f034a1	1227.18 ms	1241.96 ms	14.77 ms
8cd0d31	1201.35 ms	1217.61 ms	16.27 ms

App size

Revision	Plain	With Sentry	Diff
28a6968	21.58 KiB	418.86 KiB	397.28 KiB
6f034a1	21.58 KiB	418.86 KiB	397.28 KiB
8cd0d31	21.58 KiB	418.86 KiB	397.28 KiB

[codecov]

Codecov Report

Attention: 5 lines in your changes are missing coverage. Please review.

Comparison is base (f74904f) 89.213% compared to head (ab58b0c) 89.254%.
Report is 5 commits behind head on main.

Additional details and impacted files

@@              Coverage Diff              @@
##              main     #3540       +/-   ##
=============================================
+ Coverage   89.213%   89.254%   +0.040%     
=============================================
  Files          528       528               
  Lines        57620     57706       +86     
  Branches     20637     20678       +41     
=============================================
+ Hits         51405     51505      +100     
- Misses        5185      5287      +102     
+ Partials      1030       914      -116     

Files	Coverage Δ
Sources/Sentry/SentryBaggage.m	100.000% <ø> (ø)
...Network/SentryNetworkTrackerIntegrationTests.swift	87.218% <100.000%> (ø)
...s/SentryTests/Transaction/SentryBaggageTests.swift	100.000% <100.000%> (ø)
...erformance/Network/SentryNetworkTrackerTests.swift	97.156% <93.103%> (-0.181%)	⬇️
Sources/Sentry/SentryNetworkTracker.m	92.090% <72.727%> (-0.482%)	⬇️

... and 53 files with indirect coverage changes

---

Continue to review full report in Codecov by Sentry.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update f74904f...ab58b0c. Read the comment docs.

[philipphofmann]

LGTM.