Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

from typing import Optional

@dataclass
class VClass:
    name: Optional[str] = None
    num: Optional[int] = None

@app.route("/")
@validate(form=VClass)
def test(req, body):
    print(body.name, type(body.name))
    print(body.num, type(body.num))

curl http://localhost/

-----------RESULT---------------
None <class 'str'>
None <class 'NoneType'>

The value of body.name is the string "None" , not a NoneType.
Is this a bug?

Code snippet

No response

Expected Behavior

No response

How do you run Sanic?

As a script (app.run or Sanic.serve)

Operating System

Windows

Sanic Version

v23.3.0

Additional context

No response