Bump codecov/codecov-action from 3.1.5 to 4.0.1

[CodeBlanch]

Relates to #5293

There seem to be some breaking changes with v4 that dependabot isn't privy to: https://github.com/open-telemetry/opentelemetry-dotnet/actions/runs/7730817410/job/21078288994?pr=5293#step:9:35

[codecov]

Codecov Report

Attention: 21 lines in your changes are missing coverage. Please review.

Comparison is base (6250307) 83.38% compared to head (aeecacc) 82.98%.
Report is 53 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5294      +/-   ##
==========================================
- Coverage   83.38%   82.98%   -0.41%     
==========================================
  Files         297      272      -25     
  Lines       12531    11975     -556     
==========================================
- Hits        10449     9937     -512     
+ Misses       2082     2038      -44     

Flag	Coverage Δ
unittests	?
unittests-Instrumentation-Experimental	24.65% <47.22%> (?)
unittests-Instrumentation-Stable	24.66% <47.22%> (?)
unittests-Solution-Experimental	82.97% <77.89%> (?)
unittests-Solution-Stable	82.96% <77.89%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
....Api/Context/Propagation/TraceContextPropagator.cs	90.00% <100.00%> (+0.52%)	⬆️
...etryProtocol/Implementation/ExperimentalOptions.cs	100.00% <ø> (ø)
...tation/OpenTelemetryProtocolExporterEventSource.cs	100.00% <100.00%> (ø)
...rotocol/Implementation/OtlpLogRecordTransformer.cs	95.41% <100.00%> (+1.95%)	⬆️
....Prometheus.HttpListener/PrometheusHttpListener.cs	81.70% <100.00%> (ø)
...tation.AspNetCore/Implementation/HttpInListener.cs	89.79% <100.00%> (+0.21%)	⬆️
...AspNetCore/Implementation/HttpInMetricsListener.cs	89.74% <100.00%> (+0.26%)	⬆️
...ntation.GrpcNetClient/GrpcClientInstrumentation.cs	100.00% <100.00%> (ø)
...NetClient/GrpcClientTraceInstrumentationOptions.cs	100.00% <ø> (ø)
...ent/Implementation/GrpcClientDiagnosticListener.cs	75.80% <100.00%> (-2.77%)	⬇️
... and 14 more

... and 36 files with indirect coverage changes

[CodeBlanch]

Waiting on this before continuing with the upgrade: codecov/codecov-action#1242