Cleanup diagnostic source

[SimonCropp]

No description provided.

[mattjohnsonpint]

Some nits in comments, but LGTM so far. 👍

[SimonCropp]

@mattjohnsonpint i have made a few more changes. can u give this another once over

[codecov-commenter]

Codecov Report

Merging #1529 (27a9071) into main (cf2592b) will increase coverage by 0.01%.
The diff coverage is 79.19%.

@@            Coverage Diff             @@
##             main    #1529      +/-   ##
==========================================
+ Coverage   82.73%   82.75%   +0.01%     
==========================================
  Files         219      219              
  Lines        7398     7418      +20     
  Branches     1421     1418       -3     
==========================================
+ Hits         6121     6139      +18     
- Misses        852      856       +4     
+ Partials      425      423       -2     

Impacted Files	Coverage Δ
...rce/Internals/Extensions/KeyValuePairExtensions.cs	63.63% <63.63%> (-11.37%)	⬇️
...als/DiagnosticSource/SentryDiagnosticSubscriber.cs	59.09% <66.66%> (-0.91%)	⬇️
...gnosticSource/SentryOptionsDiagnosticExtensions.cs	66.66% <66.66%> (ø)
...ce/Internals/DiagnosticSource/SentrySqlListener.cs	80.62% <73.33%> (-1.07%)	⬇️
...Internals/DiagnosticSource/SentryEFCoreListener.cs	93.02% <97.36%> (+3.73%)	⬆️
...osticSource/SentryDiagnosticListenerIntegration.cs	100.00% <100.00%> (ø)
src/Sentry/Exceptions/SentryStackFrame.cs	78.02% <0.00%> (+1.09%)	⬆️

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