### 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
String processorTag,
            String description,
            Map<String, Object> config
        ) {
            String field = ConfigurationUtils.readStringProperty(TYPE, processorTag, config, "field");
            String targetField = ConfigurationUtils.readStringProperty(TYPE, processorTag, config, "target_field", field);
            boolean ignoreMissing = ConfigurationUtils.readBooleanProperty(TYPE, processorTag, config, "ignore_missing", false);
            double radiusDistance = Math.abs(ConfigurationUtils.readDoubleProperty(TYPE, processorTag, config, "error_distance"));
            CircleShapeFieldType circleFieldType = CircleShapeFieldType.parse(
                ConfigurationUtils.readStringProperty(TYPE, processorTag, config, "shape_type")
            );
            return new CircleProcessor(processorTag, description, field, targetField, ignoreMissing, radiusDistance, circleFieldType);
        }
    }
    enum CircleShapeFieldType {
        SHAPE,
        GEO_SHAPE;
        public static CircleShapeFieldType parse(String value) {
            EnumSet<CircleShapeFieldType> validValues = EnumSet.allOf(CircleShapeFieldType.class);
            try {
                return valueOf(value.toUpperCase(Locale.ROOT));
            } catch (IllegalArgumentException e) {
                throw new IllegalArgumentException(
                    "illegal [shape_type] value [" + value + "]. valid values are " + Arrays.toString(validValues.toArray())
                );
            }
        }
    }
}