fix: ModuleNotFoundError from wtforms 3.0.0

[shawnzhu]

Description

Stop using python2 compatible types.

ADDITIONAL INFORMATION

• Has associated issue: ModuleNotFoundError: No module named 'wtforms.compat' with WTForms 3.0.0 #1732
• Is CRUD MVC related.
• Is Auth, RBAC security related.
• Changes the security db schema.
• Introduces new feature
• Removes existing feature

[codecov]

Codecov Report

Merging #1733 (d2a9270) into master (dd07c10) will decrease coverage by 0.00%.
The diff coverage is 66.66%.

@@            Coverage Diff             @@
##           master    #1733      +/-   ##
==========================================
- Coverage   76.80%   76.80%   -0.01%     
==========================================
  Files          56       56              
  Lines        8114     8113       -1     
==========================================
- Hits         6232     6231       -1     
  Misses       1882     1882              

Flag	Coverage Δ
python	76.80% <66.66%> (-0.01%)	⬇️

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Impacted Files	Coverage Δ
flask_appbuilder/fields.py	58.99% <66.66%> (-0.30%)	⬇️

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[dpgaspar]

Thank you @shawnzhu