fix: Throw ArgumentException for empty traceId in DynamicSamplingContext

[chiliec]

Closes #5169

DynamicSamplingContext throws ArgumentOutOfRangeException when traceId is SentryId.Empty. ArgumentOutOfRangeException is meant for values outside a numeric/ordinal range; an empty id is an invalid argument, so this changes it to ArgumentException (same message, same paramName), matching the publicKey check right below it. The sampleRate / sampleRand range checks are left as ArgumentOutOfRangeException since those really are range checks.

Adds CreateFromPropagationContext_TraceId_Empty_Throws to DynamicSamplingContextTests, which reaches the constructor via SentryPropagationContext(SentryId.Empty, ...).

Verified locally (Linux, .NET SDK 10.0.401, net10.0):

dotnet test test/Sentry.Tests/Sentry.Tests.csproj -f net10.0 --filter "FullyQualifiedName~DynamicSamplingContextTests"
Passed!  - Failed: 0, Passed: 35, Skipped: 0, Total: 35

With the source change reverted the new test fails as expected (Expected: ArgumentException, Actual: ArgumentOutOfRangeException).

Only net10.0 was run here (no Android/iOS workloads on this machine).

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 74.84%. Comparing base (54bb628) to head (0c07e6c).
⚠️ Report is 6 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5599      +/-   ##
==========================================
+ Coverage   74.81%   74.84%   +0.03%     
==========================================
  Files         515      515              
  Lines       18963    18963              
  Branches     3694     3694              
==========================================
+ Hits        14187    14193       +6     
+ Misses       3894     3892       -2     
+ Partials      882      878       -4     

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[jamescrosswell]

Great - thanks @chiliec !