422 Unprocessable Entity when submitting a single item for a multiple select input

[hillstub]

Kudos on making such a nice library!!

I just came across something that I think is a bug.

When I make a form with e.g.

class SelectForm(BaseModel):
    orfs: list[str] = Field(json_schema_extra={'search_url': '/api/loci/search'})

I'm getting the 422 error when submitting the form and I've only selected one item. When I'm selecting multiple items it goes through.
This also happens with the demo page on https://fastui-demo.onrender.com/forms/select

[schatimo]

Duplicate to #122.