### Description

It would be really great if [CircleProcessor.java](https://github.com/elastic/elasticsearch/blob/0699c9351f1439e246d408fd6538deafde4087b6/x-pack/plugin/spatial/src/main/java/org/elasticsearch/xpack/spatial/ingest/CircleProcessor.java) could be published in some maven artifact.
We are thinking to convert Geoshape Circle into Geoshape Polygon on application side instead of ElasticSearch Server side. The benefits of it is that it would make possible for us to choose `error_distance` dynamically depending on different conditions.
With direct code access to [CircleProcessor.java](https://github.com/elastic/elasticsearch/blob/0699c9351f1439e246d408fd6538deafde4087b6/x-pack/plugin/spatial/src/main/java/org/elasticsearch/xpack/spatial/ingest/CircleProcessor.java) and [SpatialUtils.java](https://github.com/elastic/elasticsearch/blob/0699c9351f1439e246d408fd6538deafde4087b6/x-pack/plugin/spatial/src/main/java/org/elasticsearch/xpack/spatial/SpatialUtils.java) it would be possible to make application side custom conversion logic.
ElasticSearch version: >= 8
x-pack/plugin/spatial/src/main/java/org/elasticsearch/xpack/spatial/ingest/CircleProcessor.java
valueWrapper = Map.of("shape", obj);
        } else {
            throw new IllegalArgumentException("field [" + field + "] must be a WKT Circle or a GeoJSON Circle value");
        }
        MapXContentParser parser = new MapXContentParser(
            NamedXContentRegistry.EMPTY,
            DeprecationHandler.THROW_UNSUPPORTED_OPERATION,
            valueWrapper,
            XContentType.JSON
        );
        try {
            parser.nextToken(); 
            parser.nextToken(); 
            parser.nextToken(); 
            GeometryParserFormat geometryFormat = GeometryParserFormat.geometryFormat(parser);
            Geometry geometry = geometryFormat.fromXContent(StandardValidator.instance(true), true, true, parser);
            if (ShapeType.CIRCLE.equals(geometry.type())) {
                Circle circle = (Circle) geometry;
                int numSides = numSides(circle.getRadiusMeters());
                final Geometry polygonizedCircle = switch (circleShapeFieldType) {
                    case GEO_SHAPE -> SpatialUtils.createRegularGeoShapePolygon(circle, numSides);
                    case SHAPE -> SpatialUtils.createRegularShapePolygon(circle, numSides);
                };
                XContentBuilder newValueBuilder = XContentFactory.jsonBuilder().startObject().field("val");
                geometryFormat.toXContent(polygonizedCircle, newValueBuilder, ToXContent.EMPTY_PARAMS);
                newValueBuilder.endObject();
                Map<String, Object> newObj = XContentHelper.convertToMap(BytesReference.bytes(newValueBuilder), true, XContentType.JSON)
                    .v2();
                ingestDocument.setFieldValue(targetField, newObj.get("val"));
            } else {