test: Refactor session tracker tests with application states

[philprime]

While working on #5121 I refactored the session tracker tests for readability and adding application state to mimic the states when using actual app to trigger didBecomeActive etc.

It does not adapt the tests themselves.

#skip-changelog

[codecov]

Codecov Report

Attention: Patch coverage is 98.15498% with 5 lines in your changes missing coverage. Please review.

Project coverage is 92.900%. Comparing base (456d78e) to head (c1b6e2b).
Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
...tegrations/Session/SentrySessionTrackerTests.swift	98.154%	5 Missing ⚠️

Additional details and impacted files

@@              Coverage Diff              @@
##              main     #5251       +/-   ##
=============================================
+ Coverage   92.885%   92.900%   +0.014%     
=============================================
  Files          688       688               
  Lines        86154     86272      +118     
  Branches     31175     31195       +20     
=============================================
+ Hits         80025     80147      +122     
+ Misses        6028      6024        -4     
  Partials       101       101               

Files with missing lines	Coverage Δ
...tegrations/Session/SentrySessionTrackerTests.swift	99.024% <98.154%> (+0.430%)	⬆️

... and 5 files with indirect coverage changes

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[philipphofmann]

Thanks for doing this in an extra PR. LGTM.

[philipphofmann]

Again, LGTM.