feat: Add missing values_editable_by field for organization custom properties

[lrstanley]

Adds missing field values_editable_by for custom properties, as well as mirrors the field documentation directly from the API documentation for the other fields of custom properties.

Ref: https://docs.github.com/en/rest/orgs/custom-properties?apiVersion=2022-11-28#create-or-update-custom-properties-for-an-organization

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.91%. Comparing base (2b8c7fa) to head (2480461).
Report is 57 commits behind head on master.

Additional details and impacted files

@@ Coverage Diff @@## master #3164 +/- ##
==========================================
- Coverage 97.72% 92.91% -4.81% 
==========================================
Files 153 171 +18 Lines 13390 11502 -1888 ==========================================
- Hits 13085 10687 -2398 - Misses 215 724 +509 - Partials 90 91 +1 

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[gmlewis]

Thank you, @lrstanley !
LGTM.
Merging.