[repo] Bump Microsoft.Extensions.Logging.Configuration and clean up net462 targets

[CodeBlanch]

Relates to #5015

Changes

• Updates Microsoft.Extensions.Logging.Configuration to .NET 8 RC2.
• Cleans up "net462" being sprinkled around all over the repo.
• Uses '$(TargetFrameworkIdentifier)' == '.NETCoreApp' style in more places.

Merge requirement checklist

• CONTRIBUTING guidelines followed (nullable enabled, static analysis, etc.)
• Appropriate CHANGELOG.md files updated for non-trivial changes

[codecov]

Codecov Report

Merging #5020 (9e5c05c) into main (d91be77) will increase coverage by 0.01%.
Report is 2 commits behind head on main.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #5020      +/-   ##
==========================================
+ Coverage   83.39%   83.41%   +0.01%     
==========================================
  Files         296      296              
  Lines       12403    12403              
==========================================
+ Hits        10344    10346       +2     
+ Misses       2059     2057       -2     

Flag	Coverage Δ
unittests	83.41% <100.00%> (+0.01%)	⬆️

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

Files	Coverage Δ
src/OpenTelemetry/Metrics/Metric.cs	96.46% <100.00%> (ø)
src/Shared/HttpSemanticConventionHelper.cs	82.35% <100.00%> (ø)

... and 7 files with indirect coverage changes

[TimothyMothra]

Why this change?
Looks like this wasn't included before.
https://www.nuget.org/packages/OpenTelemetry.Instrumentation.Http/1.6.0-beta.2#dependencies-body-tab

[CodeBlanch]

Good eye there @TimothyMothra! Not totally sure. This baffled me and @utpilla a bit. We used to reference the 3.1 versions of these packages. Interestingly they have a netstandard2.0 target but NOT a net462 target. We are jumping to the .NET 8 RC versions which do have a net462 target. For some reason, using that new dedicated net462 target a bunch of these projects started complaining about missing System.Net.Http! My theory is that HttpClient is part of netstandard2.0 but NOT net462. It seems like when the netstandard2.0 bits were used the whole .NET Standard 2.0 API layer came with it including HttpClient. Best guess 😆 If you want to spend some time on it and try to figure it out I am very curious to know exactly what is going on but I decided not enough so to keep spending time on it.

[utpilla]

It seems like when the netstandard2.0 bits were used the whole .NET Standard 2.0 API layer came with it including HttpClient.

Yes, that's indeed the case here. This screenshot is from dotPeek, which shows that the netstandard2.0 bits for this package bring in netstandard2.0 APIs: