### 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
}
            if (metricDocValues.isEmpty()) {
                return null;
            }
            return new AggregateDocValuesLoader();
        }
        @Override
        public boolean hasValue() {
            return metricHasValue.isEmpty() == false;
        }
        @Override
        public void write(XContentBuilder b) throws IOException {
            if (metricHasValue.isEmpty()) {
                return;
            }
            b.startObject(simpleName);
            for (Map.Entry<Metric, SortedNumericDocValues> entry : metricDocValues.entrySet()) {
                if (metricHasValue.contains(entry.getKey())) {
                    String metricName = entry.getKey().name();
                    long value = entry.getValue().nextValue();
                    if (entry.getKey() == Metric.value_count) {
                        b.field(metricName, value);
                    } else {
                        b.field(metricName, NumericUtils.sortableLongToDouble(value));
                    }
                }
            }
            b.endObject();
        }
        private class AggregateDocValuesLoader implements DocValuesLoader {