### Elasticsearch Version

8.8.0-SNAPSHOT

### Installed Plugins

_No response_

### Java Version

_bundled_

### OS Version

MacOS

### Problem Description

API when called is returning invalid response, on the same data terms aggs query runs fine 

![image](https://user-images.githubusercontent.com/3505601/220749805-ddf0d735-60d5-4e45-85bf-941ea3076a3f.png)


When run as aggs query 

![image](https://user-images.githubusercontent.com/3505601/220764360-49f7b648-8b15-43cf-afe2-01bd62e8ebc5.png)


### Steps to Reproduce

Queries are mentioned above ^^

### Logs (if relevant)

_No response_
server/src/main/java/org/elasticsearch/index/mapper/flattened/FlattenedFieldMapper.java
}
    private final FlattenedFieldParser fieldParser;
    private final Builder builder;
    private FlattenedFieldMapper(String simpleName, MappedFieldType mappedFieldType, Builder builder) {
        super(simpleName, mappedFieldType, MultiFields.empty(), CopyTo.empty());
        this.builder = builder;
        this.fieldParser = new FlattenedFieldParser(
            mappedFieldType.name(),
            mappedFieldType.name() + KEYED_FIELD_SUFFIX,
            mappedFieldType,
            builder.depthLimit.get(),
            builder.ignoreAbove.get(),
            builder.nullValue.get()
        );
    }
    @Override
    public Map<String, NamedAnalyzer> indexAnalyzers() {
        return Map.of(mappedFieldType.name(), Lucene.KEYWORD_ANALYZER);
    }
    @Override
    protected String contentType() {
        return CONTENT_TYPE;
    }
    int depthLimit() {
        return builder.depthLimit.get();
    }
    int ignoreAbove() {
        return builder.ignoreAbove.get();
    }
    @Override