[Metrics API] Remove unnecessary auto trait implementations

[utpilla]

Changes

• Remove unnecessary Ord and PartialOrd implementation for KeyValue
• This was only used for sorting a vec of KeyValue pairs in the SDK which could be done using sort_unstable_by method anyway

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 79.2%. Comparing base (20f1204) to head (eec1be0).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #2215     +/-   ##
=======================================
- Coverage   79.2%   79.2%   -0.1%     
=======================================
  Files        122     122             
  Lines      21009   20986     -23     
=======================================
- Hits       16646   16623     -23     
  Misses      4363    4363             

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[lalitb]

LGTM with changelog