### 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_
test/framework/src/main/java/org/elasticsearch/index/mapper/MapperTestCase.java
import java.util.Optional;
import java.util.Set;
import java.util.function.Consumer;
import java.util.function.Function;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
import static java.util.stream.Collectors.toList;
import static org.hamcrest.Matchers.anyOf;
import static org.hamcrest.Matchers.containsInAnyOrder;
import static org.hamcrest.Matchers.containsString;
import static org.hamcrest.Matchers.equalTo;
import static org.hamcrest.Matchers.instanceOf;
import static org.hamcrest.Matchers.matchesPattern;
import static org.hamcrest.Matchers.nullValue;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.when;
/**
 * Base class for testing {@link Mapper}s.
 */
public abstract class MapperTestCase extends MapperServiceTestCase {
    protected abstract void minimalMapping(XContentBuilder b) throws IOException;
    /**
     * Writes the field and a sample value for it to the provided {@link XContentBuilder}.
     * To be overridden in case the field should not be written at all in documents,
     * like in the case of runtime fields.
     */
    protected void writeField(XContentBuilder builder) throws IOException {
        builder.field("field");
        builder.value(getSampleValueForDocument());
    }