[otlp] Export instrumentation scope attributes from ActivitySource.Tags

[rajkumar-rangaraj]

Fixes: OTLP Exporter part from #5701
Design discussion issue

Changes

Please provide a brief description of the changes here.

Introduces support for exporting attributes from ActivitySource.Tags via the OTLP exporter

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 85.71429% with 4 lines in your changes missing coverage. Please review.

Project coverage is 86.30%. Comparing base (6250307) to head (1ca63a6).
Report is 353 commits behind head on main.

Files with missing lines	Patch %	Lines
...metryProtocol/Implementation/ActivityExtensions.cs	85.71%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5897      +/-   ##
==========================================
+ Coverage   83.38%   86.30%   +2.91%     
==========================================
  Files         297      257      -40     
  Lines       12531    11252    -1279     
==========================================
- Hits        10449     9711     -738     
+ Misses       2082     1541     -541     

Flag	Coverage Δ
unittests	?
unittests-Project-Experimental	86.23% <85.71%> (?)
unittests-Project-Stable	86.21% <85.71%> (?)

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

Files with missing lines	Coverage Δ
...metryProtocol/Implementation/ActivityExtensions.cs	94.32% <85.71%> (-1.61%)	⬇️

... and 237 files with indirect coverage changes

[CodeBlanch]

LGTM