Scope info should only be exported for Prometheus if OpenMetrics is requested

[robertcoltheart]

Fixes #3972

Changes

otel_scope_info was mistakenly being exported for non-OpenMetrics scrapes. This fix corrects this so that it will only be exposed for OpenMetrics.

Merge requirement checklist

• CONTRIBUTING guidelines followed (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

Merging #5182 (5ff87f0) into main (3c986e8) will decrease coverage by 0.03%.
The diff coverage is 70.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5182      +/-   ##
==========================================
- Coverage   83.50%   83.48%   -0.03%     
==========================================
  Files         297      297              
  Lines       12386    12387       +1     
==========================================
- Hits        10343    10341       -2     
- Misses       2043     2046       +3     

Flag	Coverage Δ
unittests	83.48% <70.00%> (-0.03%)	⬇️

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Files	Coverage Δ
...tpListener/Internal/PrometheusCollectionManager.cs	77.77% <70.00%> (+0.19%)	⬆️

... and 9 files with indirect coverage changes

[reyang]

Consider updating the changelog by putting this PR and the previous PR under the same entry (similar to what https://github.com/open-telemetry/opentelemetry-dotnet/blob/main/src/OpenTelemetry/CHANGELOG.md#050-beta2 has - "Refactored simple export and batch export APIs (#1078 #1081 #1083 #1085 #1087 #1094 #1113 #1127 #1129 #1135)").