fix: use new API to fix test compilation error

[armcknight]

looks like this pr inadvertently broke a test on main: https://github.com/getsentry/sentry-cocoa/actions/runs/4619928851

this other pr added a test using a SentryTracer init that was removed in the other one, but CI wasn't smart enough to rerun in the PR.

This changes to the new API to use for the equivalent initialization.

#skip-changelog

[codecov]

Codecov Report

Merging #2867 (7fe7ee1) into main (bcd991b) will decrease coverage by 0.04%.
The diff coverage is 95.40%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2867      +/-   ##
==========================================
- Coverage   81.43%   81.40%   -0.04%     
==========================================
  Files         261      262       +1     
  Lines       24390    24363      -27     
  Branches    10814    10817       +3     
==========================================
- Hits        19863    19833      -30     
+ Misses       4023     3916     -107     
- Partials      504      614     +110     

Impacted Files	Coverage Δ
Sources/Sentry/SentryTracer.m	96.20% <92.15%> (-0.57%)	⬇️
Sources/Sentry/SentryHub.m	95.87% <100.00%> (-0.19%)	⬇️
Sources/Sentry/SentryPerformanceTracker.m	100.00% <100.00%> (ø)
Sources/Sentry/SentryTracerConfiguration.m	100.00% <100.00%> (ø)
Sources/Sentry/SentryUIEventTracker.m	100.00% <100.00%> (ø)

... and 27 files with indirect coverage changes

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