### Elasticsearch Version

main

### Installed Plugins

_No response_

### Java Version

_bundled_

### OS Version

all

### Problem Description

The `filter` agg should run as `filters` because the `filters` agg has tons of optimizations, some of them are even around when running with a single filter. At a minimum we should optimize the `filter` agg in the same way as `filters`, but I think it's easier if we just run it as `filters`.

### Steps to Reproduce

see above

### Logs (if relevant)

_No response_
server/src/test/java/org/elasticsearch/search/aggregations/bucket/filter/FilterAggregatorTests.java
}
    public void testEmpty() throws Exception {
        Directory directory = newDirectory();
        RandomIndexWriter indexWriter = new RandomIndexWriter(random(), directory);
        indexWriter.close();
        IndexReader indexReader = DirectoryReader.open(directory);
        IndexSearcher indexSearcher = newSearcher(indexReader, true, true);
        QueryBuilder filter = QueryBuilders.termQuery("field", randomAlphaOfLength(5));
        FilterAggregationBuilder builder = new FilterAggregationBuilder("test", filter);
        InternalFilter response = searchAndReduce(new AggTestConfig(indexSearcher, builder, fieldType));
        assertEquals(response.getDocCount(), 0);
        assertFalse(AggregationInspectionHelper.hasValue(response));
        indexReader.close();
        directory.close();
    }
    public void testRandom() throws Exception {
        Directory directory = newDirectory();
        RandomIndexWriter indexWriter = new RandomIndexWriter(random(), directory);
        int numDocs = randomIntBetween(100, 200);
        int maxTerm = randomIntBetween(10, 50);
        int[] expectedBucketCount = new int[maxTerm];
        Document document = new Document();
        for (int i = 0; i < numDocs; i++) {
            if (frequently()) {
                
                indexWriter.commit();
            }
            int value = randomInt(maxTerm - 1);
            expectedBucketCount[value] += 1;
            document.add(new Field("field", Integer.toString(value), KeywordFieldMapper.Defaults.FIELD_TYPE));