GEOPY-2525: Support placeholderText in uijson forms

[benk-mira]

GEOPY-2525 - Support placeholderText in uijson forms

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.86%. Comparing base (1a8c416) to head (616da8e).
⚠️ Report is 7 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #811      +/-   ##
===========================================
- Coverage    90.88%   90.86%   -0.02%     
===========================================
  Files          113      113              
  Lines         9873     9875       +2     
  Branches      1838     1838              
===========================================
  Hits          8973     8973              
- Misses         487      488       +1     
- Partials       413      414       +1     

Files with missing lines	Coverage Δ
geoh5py/ui_json/forms.py	95.87% <100.00%> (+0.02%)	⬆️

... and 3 files with indirect coverage changes

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[domfournier]

Something is missing here to convert the alias "placeholderText" to snake_case. I think it should be placeholder_text