Right now filter aggregations run in "compatible" mode if the top level query is `bool: {filter: { match_all: {}}}}` - but this really just just `match_all` in disguise. We should just run in filter-by-filter mode here.
server/src/test/java/org/elasticsearch/search/aggregations/bucket/filter/FiltersAggregatorTests.java
public void testDocValuesFieldExistsForNumberWithoutData() throws IOException {
        docValuesFieldExistsNoDataTestCase(
            new NumberFieldMapper.NumberFieldType(
                "f",
                randomFrom(NumberFieldMapper.NumberType.values()),
                true,
                false,
                true,
                true,
                null,
                Map.of(),
                null,
                false,
                null
            )
        );
    }
    public void testDocValuesFieldExistsForKeyword() throws IOException {
        KeywordFieldMapper.KeywordFieldType ft = new KeywordFieldMapper.KeywordFieldType("f", true, true, Map.of());
        docValuesFieldExistsTestCase(new ExistsQueryBuilder("f"), ft, false, i -> {
            BytesRef text = new BytesRef(randomAlphaOfLength(5));
            return List.of(new Field("f", text, KeywordFieldMapper.Defaults.FIELD_TYPE), new SortedSetDocValuesField("f", text));
        });
    }
    public void testDocValuesFieldExistsForKeywordWithoutData() throws IOException {
        docValuesFieldExistsNoDataTestCase(new KeywordFieldMapper.KeywordFieldType("f", true, true, Map.of()));
    }
    private void docValuesFieldExistsTestCase(
        QueryBuilder exists,
        MappedFieldType fieldType,