fix: Round-trip Enum and Categorical metadata in plugins

[orlp]

Fixes #22094.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 81.42%. Comparing base (11643a6) to head (cb8e78c).
Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #23588      +/-   ##
==========================================
+ Coverage   81.41%   81.42%   +0.01%     
==========================================
  Files        1641     1641              
  Lines      222360   222353       -7     
  Branches     2835     2835              
==========================================
+ Hits       181029   181058      +29     
+ Misses      40632    40596      -36     
  Partials      699      699              

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