[BUG] global configuration of encoder/decoder for type T is not used for Optional[T] field

[PJCampi]

Description

Let's say I register a custom encoder/decoder for type T in the global_config. I would expect that a dataclass with a field of type Optional[T] to use the encoder/decoder registered. Instead I have to manually register the same encoder for the type Optional[T] for the encoder to be picked up.
_user_overrides_or_exts does not unwrap the optional type.

Code snippet that reproduces the issue

from dataclasses import dataclass
from dataclasses_json import dataclass_json, global_config
from datetime import date
from typing import Optional

global_config.encoders[date] = date.isoformat
# global_config.encoders[Optional[date]] = date.isoformat

@dataclass_json
@dataclass
class DataClassWithIsoDatetime:
    created_at: Optional[date] = None

print(DataClassWithIsoDatetime(date.today()).to_json())

Describe the results you expected

{"created_at": "2023-08-08"}

Python version you are using

3.9

Environment description

dataclasses-json==0.5.14

[george-zubrienko]

Should be solved in v1, but I suggest we still fix this in v0

[PJCampi]

This is becoming a bigger problem for me (global configs are also not applied from collections or mappings) so I will try to see if I can fix this tomorrow. It should be relatively simple.

[PJCampi]

I have a fix for the bug. I can create a PR if someone can grant me write access to the repo.

[george-zubrienko]

@PJCampi tagged you in another issue - please fork the repo and create a PR, you do not need contributor access to the repo itself

[PJCampi]

here you go: #524