fix: Ensure make_array always returns a tomlkit array type.

[leemars]

Pull Request Checklist

• A news fragment is added in news/ describing what is new.
• Test cases added for changed code.

Describe what you have changed in this PR.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 85.23%. Comparing base (72c3c6b) to head (ad75fcf).
⚠️ Report is 52 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3586   +/-   ##
=======================================
  Coverage   85.23%   85.23%           
=======================================
  Files         118      118           
  Lines       12015    12015           
  Branches     1960     1960           
=======================================
  Hits        10241    10241           
  Misses       1209     1209           
  Partials      565      565           

Flag	Coverage Δ
unittests	85.09% <100.00%> (ø)

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