### 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
if (ft.isAggregatable()) {
            try {
                ft.fielddataBuilder(FieldDataContext.noRuntimeFields("aggregation_test"));
            } catch (Exception e) {
                fail("Unexpected exception when fetching field data from aggregatable field type");
            }
        } else {
            expectThrows(IllegalArgumentException.class, () -> ft.fielddataBuilder(FieldDataContext.noRuntimeFields("aggregation_test")));
        }
    }
    /**
     * Does this field mapper support {@code ignore_malformed}?
     */
    protected abstract boolean supportsIgnoreMalformed();
    /**
     * Build an {@link ExampleMalformedValue} that parses a string.
     */
    protected final ExampleMalformedValue exampleMalformedValue(String value) {
        return exampleMalformedValue(b -> b.value(value));
    }
    /**
     * Build an {@link ExampleMalformedValue} for arbitrary xcontent.
     */
    protected final ExampleMalformedValue exampleMalformedValue(CheckedConsumer<XContentBuilder, IOException> value) {
        return new ExampleMalformedValue(this::minimalMapping, value, equalTo("unset"));
    }
    /**
     * An example of a malformed value.
     */
    public static class ExampleMalformedValue {