### Elasticsearch Version

main

### Installed Plugins

_No response_

### Java Version

_bundled_

### OS Version

all

### Problem Description

When you configure an `aggregate_metric_double` with `ignore_malformed: true` and send a malformed value we create an `_ignored` field with three values, `field.value_count`, `field.min`, and `field.max`. This is the only top "composite" field that creates `_ignored` values for its children. Things like shape only create `field` in `_ignored`. Is there a good reason for `aggregate_metric_double` to be different?

### Steps to Reproduce

see above

### Logs (if relevant)

_No response_
x-pack/plugin/mapper-aggregate-metric/src/main/java/org/elasticsearch/xpack/aggregatemetric/mapper/AggregateDoubleMetricFieldMapper.java
*/
        private final Parameter<MetricType> timeSeriesMetric;
        /**
         * Set the default metric so that query operations are delegated to it.
         */
        private final Parameter<Metric> defaultMetric = new Parameter<>(Names.DEFAULT_METRIC, false, () -> null, (n, c, o) -> {
            try {
                return Metric.valueOf(o.toString());
            } catch (IllegalArgumentException e) {
                throw new IllegalArgumentException("Metric [" + o.toString() + "] is not supported.", e);
            }
        }, m -> toType(m).defaultMetric, XContentBuilder::field, Objects::toString);
        private final Version indexCreatedVersion;
        public Builder(String name, Boolean ignoreMalformedByDefault, Version indexCreatedVersion) {
            super(name);
            this.ignoreMalformed = Parameter.boolParam(
                Names.IGNORE_MALFORMED,
                true,
                m -> toType(m).ignoreMalformed,
                ignoreMalformedByDefault
            );
            this.timeSeriesMetric = TimeSeriesParams.metricParam(m -> toType(m).metricType, MetricType.gauge);
            this.indexCreatedVersion = Objects.requireNonNull(indexCreatedVersion);
        }
        @Override
        protected Parameter<?>[] getParameters() {
            return new Parameter<?>[] { ignoreMalformed, metrics, defaultMetric, meta, timeSeriesMetric };
        }
        public Builder metric(MetricType metric) {
            this.timeSeriesMetric.setValue(metric);