### 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/test/java/org/elasticsearch/xpack/aggregatemetric/mapper/AggregateDoubleMetricFieldMapperTests.java
mapper.parse(source(b -> b.startObject("field").field("min", 10.0).field("max", 50.0).field("value_count", 14).endObject()));
    }
    private void randomMapping(XContentBuilder b, int randomNumber) throws IOException {
        b.field("type", CONTENT_TYPE);
        switch (randomNumber) {
            case 0 -> b.field(METRICS_FIELD, new String[] { "min" }).field(DEFAULT_METRIC, "min");
            case 1 -> b.field(METRICS_FIELD, new String[] { "max" }).field(DEFAULT_METRIC, "max");
            case 2 -> b.field(METRICS_FIELD, new String[] { "value_count" }).field(DEFAULT_METRIC, "value_count");
            case 3 -> b.field(METRICS_FIELD, new String[] { "sum" }).field(DEFAULT_METRIC, "sum");
        }
    }
    /**
     * Test inserting a document containing an array of metrics. An exception must be thrown.
     */
    public void testParseArrayValue() throws Exception {
        int randomNumber = randomIntBetween(0, 3);
        DocumentMapper mapper = createDocumentMapper(fieldMapping(b -> randomMapping(b, randomNumber)));
        Exception e = expectThrows(MapperParsingException.class, () -> mapper.parse(source(b -> {
            b.startArray("field").startObject();
            switch (randomNumber) {
                case 0 -> b.field("min", 10.0);
                case 1 -> b.field("max", 50);
                case 2 -> b.field("value_count", 3);
                case 3 -> b.field("sum", 100.0);
            }
            b.endObject();
            b.startObject();
            switch (randomNumber) {
                case 0 -> b.field("min", 20.0);