test: Add Scope attributes test cases for metrics

[Shunpoco]

Fixes #2702

Changes

Add additional unit test to cover Scope attributes for metrics.
I don't add any test cases for Logger/Tracer because their with_scope() method creates new Logger/Tracer regardless of Scope attribute's identity (Will we change the methods in the future?).

Merge requirement checklist

• CONTRIBUTING guidelines followed
• Unit tests added/updated (if applicable)
• Appropriate CHANGELOG.md files updated for non-trivial, user-facing changes
• Changes in public API reviewed (if applicable)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 79.4%. Comparing base (1583e70) to head (d2f7f2b).
Report is 1 commits behind head on main.

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #2736   +/-   ##
=====================================
  Coverage   79.4%   79.4%           
=====================================
  Files        123     123           
  Lines      22736   22770   +34     
=====================================
+ Hits       18058   18093   +35     
+ Misses      4678    4677    -1     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[cijothomas]

I don't add any test cases for Logger/Tracer because their with_scope() method creates new Logger/Tracer regardless of Scope attribute's identity (Will we change the methods in the future?).

Not likely to change as it is not required. For Metrics this is important to get pre-aggregation correctly

[cijothomas]

Thanks!