Fix vault plugin

[pinmarva]

The vault plugin causes the application crashes when trying to get plugins:

ERROR in app: Exception on /api/1/plugins [GET]
Traceback (most recent call last):
  File "/opt/venv/lib/python3.8/site-packages/flask/app.py", line 1484, in full_dispatch_request
    rv = self.dispatch_request()
  File "/opt/venv/lib/python3.8/site-packages/flask/app.py", line 1469, in dispatch_request
    return self.ensure_sync(self.view_functions[rule.endpoint])(**view_args)
  File "/opt/venv/lib/python3.8/site-packages/flask_restful/__init__.py", line 493, in wrapper
    return self.make_response(data, code, headers=headers)
  File "/opt/venv/lib/python3.8/site-packages/flask_restful/__init__.py", line 522, in make_response
    resp = self.representations[mediatype](data, *args, **kwargs)
  File "/opt/venv/lib/python3.8/site-packages/flask_restful/representations/json.py", line 21, in output_json
    dumped = dumps(data, **settings) + "\n"
  File "/usr/lib/python3.8/json/__init__.py", line 231, in dumps
    return _default_encoder.encode(obj)
  File "/usr/lib/python3.8/json/encoder.py", line 199, in encode
    chunks = self.iterencode(o, _one_shot=True)
  File "/usr/lib/python3.8/json/encoder.py", line 257, in iterencode
    return _iterencode(o, 0)
  File "/usr/lib/python3.8/json/encoder.py", line 179, in default
    raise TypeError(f'Object of type {o.__class__.__name__} '
TypeError: Object of type function is not JSON serializable
Exception on /api/1/plugins [GET]
Traceback (most recent call last):
  File "/opt/venv/lib/python3.8/site-packages/flask/app.py", line 1484, in full_dispatch_request
    rv = self.dispatch_request()
  File "/opt/venv/lib/python3.8/site-packages/flask/app.py", line 1469, in dispatch_request
    return self.ensure_sync(self.view_functions[rule.endpoint])(**view_args)
  File "/opt/venv/lib/python3.8/site-packages/flask_restful/__init__.py", line 493, in wrapper
    return self.make_response(data, code, headers=headers)
  File "/opt/venv/lib/python3.8/site-packages/flask_restful/__init__.py", line 522, in make_response
    resp = self.representations[mediatype](data, *args, **kwargs)
  File "/opt/venv/lib/python3.8/site-packages/flask_restful/representations/json.py", line 21, in output_json
    dumped = dumps(data, **settings) + "\n"
  File "/usr/lib/python3.8/json/__init__.py", line 231, in dumps
    return _default_encoder.encode(obj)
  File "/usr/lib/python3.8/json/encoder.py", line 199, in encode
    chunks = self.iterencode(o, _one_shot=True)
  File "/usr/lib/python3.8/json/encoder.py", line 257, in iterencode
    return _iterencode(o, 0)
  File "/usr/lib/python3.8/json/encoder.py", line 179, in default
    raise TypeError(f'Object of type {o.__class__.__name__} '
TypeError: Object of type function is not JSON serializable
Exception on /api/1/plugins [GET]
Traceback (most recent call last):
  File "/opt/venv/lib/python3.8/site-packages/flask/app.py", line 1484, in full_dispatch_request
    rv = self.dispatch_request()
  File "/opt/venv/lib/python3.8/site-packages/flask/app.py", line 1469, in dispatch_request
    return self.ensure_sync(self.view_functions[rule.endpoint])(**view_args)
  File "/opt/venv/lib/python3.8/site-packages/flask_restful/__init__.py", line 493, in wrapper
    return self.make_response(data, code, headers=headers)
  File "/opt/venv/lib/python3.8/site-packages/flask_restful/__init__.py", line 522, in make_response
    resp = self.representations[mediatype](data, *args, **kwargs)
  File "/opt/venv/lib/python3.8/site-packages/flask_restful/representations/json.py", line 21, in output_json
    dumped = dumps(data, **settings) + "\n"
  File "/usr/lib/python3.8/json/__init__.py", line 231, in dumps
    return _default_encoder.encode(obj)
  File "/usr/lib/python3.8/json/encoder.py", line 199, in encode
    chunks = self.iterencode(o, _one_shot=True)
  File "/usr/lib/python3.8/json/encoder.py", line 257, in iterencode
    return _iterencode(o, 0)
  File "/usr/lib/python3.8/json/encoder.py", line 179, in default
    raise TypeError(f'Object of type {o.__class__.__name__} '
TypeError: Object of type function is not JSON serializable

The problem is the function "from validators.url import url":
'url' returns "True" when validation is successful, and returns "ValidationError(func=url, args={'value': 'whatever'})" when url validation fails.
In the PR, the return of the function "url" is converted to boolean.

[jmcrawford45]

Thank you for putting together a fix for this. Could you add a unit test which fails on main currently demonstrating this issue and that the fix addresses it?

[coveralls]

coverage: 75.289% (-0.2%) from 75.446%
when pulling 10961ff on pinmarva:fix_vault_plugin
into b889412 on Netflix:main.

[pinmarva]

Added the requested tests.