[Instrumentation.AspNet] fix metric description

[puckpuck]

Fixes #4169
Is a continuation of #4171
Initiated by this issue on the OpenTelemetry Demo

Changes

Fixes the metric description to conform with specifications and prevent errors from the Prometheus exporter in the collector.

• Appropriate CHANGELOG.md updated for non-trivial changes
• Design discussion issue #
• Changes in public API reviewed

[codecov]

Codecov Report

Merging #1063 (a5de5aa) into main (6dc0417) will not change coverage.
The diff coverage is 100.00%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1063   +/-   ##
=======================================
  Coverage   69.88%   69.88%           
=======================================
  Files         203      203           
  Lines        7783     7783           
=======================================
  Hits         5439     5439           
  Misses       2344     2344           

Impacted Files	Coverage Δ
...xporter.Instana/TracerProviderBuilderExtensions.cs	0.00% <ø> (ø)
...ion.AspNet/Implementation/HttpInMetricsListener.cs	100.00% <100.00%> (ø)

[cartersocha]

Hey @utpilla could we get this fix released or is there a release timeline? We'd like to close a bug in the demo and it's blocked on this

[cartersocha]

Or @cijothomas ?

[cijothomas]

Releases from contrib repo are based on explicit asks only.
Please use this to request a release:
https://github.com/open-telemetry/opentelemetry-dotnet-contrib/blob/main/CONTRIBUTING.md#how-to-request-for-release-of-package