### 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/main/java/org/elasticsearch/search/aggregations/bucket/filter/FilterAggregationBuilder.java
public FilterAggregationBuilder(String name, QueryBuilder filter) {
        super(name);
        if (filter == null) {
            throw new IllegalArgumentException("[filter] must not be null: [" + name + "]");
        }
        this.filter = filter;
    }
    protected FilterAggregationBuilder(
        FilterAggregationBuilder clone,
        AggregatorFactories.Builder factoriesBuilder,
        Map<String, Object> metadata
    ) {
        super(clone, factoriesBuilder, metadata);
        this.filter = clone.filter;
    }
    @Override
    protected AggregationBuilder shallowCopy(AggregatorFactories.Builder factoriesBuilder, Map<String, Object> metadata) {
        return new FilterAggregationBuilder(this, factoriesBuilder, metadata);
    }
    /**
     * Read from a stream.
     */
    public FilterAggregationBuilder(StreamInput in) throws IOException {
        super(in);
        filter = in.readNamedWriteable(QueryBuilder.class);
    }
    @Override
    public boolean supportsSampling() {
        return true;
    }