### 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
* <p>
     * Generally this method covers many many random cases but rarely. So if
     * it fails its generally a good idea to capture its randomized
     * parameters into a new method so we can be sure we consistently test
     * any unique and interesting failure case. See the tests for
     * {@link DateFieldMapper} for some examples.
     */
    public final void testFetchMany() throws IOException {
        MapperService mapperService = randomFetchTestMapper();
        try {
            MappedFieldType ft = mapperService.fieldType("field");
            int count = between(2, 10);
            List<Object> values = new ArrayList<>(count);
            while (values.size() < count) {
                values.add(generateRandomInputValue(ft));
            }
            assertFetch(mapperService, "field", values, randomFetchTestFormat());
        } finally {
            assertParseMinimalWarnings();
        }
    }
    protected final MapperService randomFetchTestMapper() throws IOException {
        return createMapperService(mapping(b -> {
            b.startObject("field");
            randomFetchTestFieldConfig(b);
            b.endObject();
        }));
    }
    /**
     * Field configuration for {@link #testFetch} and {@link #testFetchMany}.