fix: swagger missing nonce

[dpgaspar]

Description

Adds missing nonce on Swagger

ADDITIONAL INFORMATION

• Has associated issue:
• Is CRUD MVC related.
• Is Auth, RBAC security related.
• Changes the security db schema.
• Introduces new feature
• Removes existing feature

[codecov]

Codecov Report

Merging #2116 (e298643) into master (b2cec68) will decrease coverage by 0.34%.
Report is 23 commits behind head on master.
The diff coverage is 67.08%.

@@            Coverage Diff             @@
##           master    #2116      +/-   ##
==========================================
- Coverage   78.62%   78.29%   -0.34%     
==========================================
  Files          72       72              
  Lines        8698     8699       +1     
==========================================
- Hits         6839     6811      -28     
- Misses       1859     1888      +29     

Flag	Coverage Δ
python	78.29% <67.08%> (-0.34%)	⬇️

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Files Changed	Coverage Δ
flask_appbuilder/baseviews.py	89.71% <0.00%> (-0.19%)	⬇️
flask_appbuilder/forms.py	98.16% <0.00%> (ø)
flask_appbuilder/models/group.py	55.00% <0.00%> (-17.78%)	⬇️
flask_appbuilder/models/mongoengine/interface.py	78.00% <0.00%> (ø)
flask_appbuilder/security/decorators.py	94.68% <ø> (ø)
flask_appbuilder/security/registerviews.py	31.88% <0.00%> (ø)
flask_appbuilder/security/sqla/apis/role/schema.py	100.00% <ø> (ø)
flask_appbuilder/models/sqla/interface.py	83.07% <20.00%> (ø)
flask_appbuilder/security/mongoengine/manager.py	66.15% <23.80%> (ø)
flask_appbuilder/security/sqla/manager.py	75.50% <34.48%> (ø)
... and 11 more