[api-logs] Remove unneeded if check in LogRecordAttributeList

[SimonCropp]

Fixes #
Design discussion issue #

Changes

remove if (count > 0) in LogRecordAttributeList since above there is

        if (count <= 0)
        {
            return Empty;
        }

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

All modified and coverable lines are covered by tests ✅

Project coverage is 86.40%. Comparing base (fdca498) to head (6572399).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6076      +/-   ##
==========================================
+ Coverage   86.38%   86.40%   +0.01%     
==========================================
  Files         257      257              
  Lines       11679    11656      -23     
==========================================
- Hits        10089    10071      -18     
+ Misses       1590     1585       -5     

Files with missing lines	Coverage Δ
...c/OpenTelemetry.Api/Logs/LogRecordAttributeList.cs	66.66% <ø> (-2.36%)	⬇️