refactor!: modify json serialization of owned column

[stuarttimwhite]

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Rationale for this change

What changes are included in this PR?

Are these changes tested?

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.44%. Comparing base (4312e52) to head (ef1c5be).
⚠️ Report is 5 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1119      +/-   ##
==========================================
- Coverage   96.45%   96.44%   -0.02%     
==========================================
  Files         293      291       -2     
  Lines       52149    51748     -401     
==========================================
- Hits        50301    49908     -393     
+ Misses       1848     1840       -8     

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