[Draft] Add support for .NET 9 Advice API

[rajkumar-rangaraj]

Fixes #5487
Design discussion issue #

Changes

Please provide a brief description of the changes here.

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

Attention: Patch coverage is 82.60870% with 4 lines in your changes missing coverage. Please review.

Project coverage is 86.21%. Comparing base (6250307) to head (6c337a5).
Report is 321 commits behind head on main.

Files with missing lines	Patch %	Lines
src/OpenTelemetry/Metrics/MetricStreamIdentity.cs	82.60%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5854      +/-   ##
==========================================
+ Coverage   83.38%   86.21%   +2.82%     
==========================================
  Files         297      257      -40     
  Lines       12531    11190    -1341     
==========================================
- Hits        10449     9647     -802     
+ Misses       2082     1543     -539     

Flag	Coverage Δ
unittests	?
unittests-Project-Experimental	85.94% <82.60%> (?)
unittests-Project-Stable	86.17% <82.60%> (?)

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

Files with missing lines	Coverage Δ
src/OpenTelemetry/Metrics/MetricStreamIdentity.cs	86.44% <82.60%> (-0.23%)	⬇️

... and 222 files with indirect coverage changes