[repo] Prepare to .NET9 - reenable analysis level

[Kielek]

Changes

Follow up #2251

All leftovers. Enables <AnalysisLevel>latest-all</AnalysisLevel>

PR is a bit bigger than usual, but I would like to finish finally this effort. It should be safe to review commits independently.
Most important commits:

• c1f1f3d
• 88321b3
• f78668a
• 6c2101c

Merge requirement checklist

• CONTRIBUTING guidelines followed (license requirements, nullable enabled, static analysis, etc.)
• [ ] Unit tests added/updated
• [ ] Appropriate CHANGELOG.md files updated for non-trivial changes
• [ ] Changes in public API reviewed (if applicable)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 67.82%. Comparing base (71655ce) to head (e1b3c61).
Report is 618 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2350      +/-   ##
==========================================
- Coverage   73.91%   67.82%   -6.10%     
==========================================
  Files         267      363      +96     
  Lines        9615    13394    +3779     
==========================================
+ Hits         7107     9084    +1977     
- Misses       2508     4310    +1802     

Flag	Coverage Δ
unittests-Contrib.Shared.Tests	84.04% <100.00%> (?)
unittests-Exporter.Geneva	47.44% <100.00%> (?)
unittests-Exporter.InfluxDB	95.14% <ø> (?)
unittests-Exporter.Instana	74.86% <ø> (?)
unittests-Exporter.OneCollector	94.57% <ø> (?)
unittests-Exporter.Stackdriver	79.26% <ø> (?)
unittests-Extensions	88.63% <100.00%> (?)
unittests-Extensions.Enrichment	100.00% <ø> (?)
unittests-Instrumentation.AWS	84.55% <100.00%> (?)
unittests-Instrumentation.AspNet	77.00% <100.00%> (?)
unittests-Instrumentation.AspNetCore	70.33% <ø> (?)
unittests-Instrumentation.ConfluentKafka	14.37% <ø> (?)
unittests-Instrumentation.ElasticsearchClient	80.12% <ø> (?)
unittests-Instrumentation.EntityFrameworkCore	57.06% <100.00%> (?)
unittests-Instrumentation.EventCounters	76.36% <ø> (?)
unittests-Instrumentation.GrpcCore	91.42% <ø> (?)
unittests-Instrumentation.GrpcNetClient	79.61% <ø> (?)
unittests-Instrumentation.Hangfire	93.58% <ø> (?)
unittests-Instrumentation.Http	62.18% <100.00%> (?)
unittests-Instrumentation.Owin	88.12% <ø> (?)
unittests-Instrumentation.Process	100.00% <100.00%> (?)
unittests-Instrumentation.Quartz	78.76% <ø> (?)
unittests-Instrumentation.Runtime	100.00% <ø> (?)
unittests-Instrumentation.SqlClient	91.69% <100.00%> (?)
unittests-Instrumentation.StackExchangeRedis	68.26% <ø> (?)
unittests-Instrumentation.Wcf	49.55% <100.00%> (?)
unittests-PersistentStorage	65.21% <ø> (?)
unittests-Resources.AWS	79.16% <ø> (?)
unittests-Resources.Azure	84.56% <ø> (?)
unittests-Resources.Container	67.34% <ø> (?)
unittests-Resources.Gcp	71.15% <ø> (?)
unittests-Resources.Host	73.91% <ø> (?)
unittests-Resources.OperatingSystem	75.40% <ø> (?)
unittests-Resources.Process	100.00% <ø> (?)
unittests-Resources.ProcessRuntime	78.26% <ø> (?)
unittests-Sampler.AWS	88.12% <ø> (?)

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

Files with missing lines	Coverage Δ
...rter.Geneva/Metrics/GenevaMetricExporterOptions.cs	100.00% <100.00%> (ø)
...ons/Internal/ActivityEventAttachingLogProcessor.cs	88.23% <100.00%> (-5.89%)	⬇️
...ry.Extensions/Internal/DefaultLogStateConverter.cs	87.50% <100.00%> (ø)
...c/OpenTelemetry.Extensions/Internal/RateLimiter.cs	100.00% <100.00%> (ø)
...nTelemetry.Extensions/Trace/RateLimitingSampler.cs	100.00% <100.00%> (ø)
...AWS/Implementation/AWSTracingPipelineCustomizer.cs	90.90% <100.00%> (+3.40%)	⬆️
...on.AspNet/Implementation/HttpRequestRouteHelper.cs	100.00% <100.00%> (ø)
...mplementation/EntityFrameworkDiagnosticListener.cs	53.03% <100.00%> (+0.64%)	⬆️
...tp/Implementation/HttpHandlerDiagnosticListener.cs	72.95% <100.00%> (ø)
...entation.Process/MeterProviderBuilderExtensions.cs	100.00% <100.00%> (ø)
... and 8 more

... and 369 files with indirect coverage changes