Make GeoPolygon interiors optional

[agourlay]

In #2315 we made the interiors field of geo polygons effectively optional by performing the validation in a shadow type.

We have tests showing that it works fine but we forgot to propagate the change to the type which provided the JSON schema.

Issue discovered while updating the Python client qdrant/qdrant-client#325

[agourlay]

here is the important change.

Scrolling above you will find the shadow type which already had the optional field

#[derive(Deserialize)]
pub struct GeoPolygonShadow {
    pub exterior: GeoLineString,
    pub interiors: Option<Vec<GeoLineString>>,
}

[zzzz-vincent]

Thanks for capturing!