Implementation of formfield_for_choice_field makes overriding choices clumsy

[Daspy11]

I have an inline admin where I'm trying to override the choices used. The issue with the implementation of this method in Unfold's base in admin.py is that if you modify the choices kwarg, it will be overridden by the base choices unless you also pass the widget kwarg, and doing that requires importing some internal Unfold stuff in an unclean way.

Current

    def formfield_for_choice_field(
        self, db_field: Field, request: HttpRequest, **kwargs
    ) -> TypedChoiceField:
        # Overrides widget for CharFields which have choices attribute
        if "widget" not in kwargs:
            if db_field.name in self.radio_fields:
                kwargs["widget"] = UnfoldAdminRadioSelectWidget(
                    radio_style=self.radio_fields[db_field.name]
                )
            else:
                kwargs["widget"] = UnfoldAdminSelectWidget()

            kwargs["choices"] = db_field.get_choices(
                include_blank=db_field.blank, blank_choice=[("", _("Select value"))]
            )

        return super().formfield_for_choice_field(db_field, request, **kwargs)

What it should be

    def formfield_for_choice_field(
        self, db_field: Field, request: HttpRequest, **kwargs
    ) -> TypedChoiceField:
        if "widget" not in kwargs:
            if db_field.name in self.radio_fields:
                kwargs["widget"] = UnfoldAdminRadioSelectWidget(
                    radio_style=self.radio_fields[db_field.name]
                )
            else:
                kwargs["widget"] = UnfoldAdminSelectWidget()
        if "choices" not in kwargs:
            kwargs["choices"] = db_field.get_choices(
                include_blank=db_field.blank, blank_choice=[("", _("Select value"))]
            )

        return super().formfield_for_choice_field(db_field, request, **kwargs)

[lukasvinclav]

Thanks for report. Fixed #539