Accept uuid.UUID objects in UUID validator

[TurnrDev]

Fixes #549 and pallets-eco/flask-admin#1444

Better implementation of #609

[TurnrDev]

Test Result:

================================================= test session starts =================================================
platform win32 -- Python 3.10.2, pytest-7.2.1, pluggy-1.0.0 -- C:\Users\JayTurner\.virtualenvs\wtforms-V-P53RkO\Scripts\python.exe
cachedir: .pytest_cache
rootdir: C:\Users\JayTurner\Personal\wtforms, configfile: setup.cfg
collected 7 items

tests/validators/test_uuid.py::test_valid_uuid_passes[2bc1c94f-0deb-43e9-92a1-4775189ec9f8] PASSED               [ 14%]
tests/validators/test_uuid.py::test_valid_uuid_passes[2bc1c94f0deb43e992a14775189ec9f8] PASSED                   [ 28%]
tests/validators/test_uuid.py::test_valid_uuid_passes[uuid_val2] PASSED                                          [ 42%]
tests/validators/test_uuid.py::test_bad_uuid_raises[2bc1c94f-deb-43e9-92a1-4775189ec9f8] PASSED                  [ 57%]
tests/validators/test_uuid.py::test_bad_uuid_raises[2bc1c94f-0deb-43e9-92a1-4775189ec9f] PASSED                  [ 71%]
tests/validators/test_uuid.py::test_bad_uuid_raises[gbc1c94f-0deb-43e9-92a1-4775189ec9f8] PASSED                 [ 85%]
tests/validators/test_uuid.py::test_bad_uuid_raises[2bc1c94f 0deb-43e9-92a1-4775189ec9f8] PASSED                 [100%]

================================================== 7 passed in 0.02s ==================================================

[TurnrDev]

I have reformted the imports on re the tox style checks and added a changelog entry

[azmeuk]

Hi @TurnrDev
I was thinking about this PR and I was wondering: if the validator gets UUID objects in the end, that means that it has been initialized (with model data for instance), and it has been validated without formdata (else the formdata would have been validated, and formdata can only be strings). Out of curiosity, why do you validate your model data?

[TurnrDev]

Hi @azmeuk

I encoured this issue when using flask-admin with sqlalchemy. I can't say for sure why they're doing what they're doing.