### 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
@Override
    protected void doWriteTo(StreamOutput out) throws IOException {
        out.writeNamedWriteable(filter);
    }
    @Override
    public BucketCardinality bucketCardinality() {
        return BucketCardinality.ONE;
    }
    @Override
    protected AggregationBuilder doRewrite(QueryRewriteContext queryRewriteContext) throws IOException {
        QueryBuilder result = Rewriteable.rewrite(filter, queryRewriteContext);
        if (result != filter) {
            return new FilterAggregationBuilder(getName(), result);
        }
        return this;
    }
    @Override
    protected AggregatorFactory doBuild(
        AggregationContext context,
        AggregatorFactory parent,
        AggregatorFactories.Builder subFactoriesBuilder
    ) throws IOException {
        return new FilterAggregatorFactory(name, filter, context, parent, subFactoriesBuilder, metadata);
    }
    @Override
    protected XContentBuilder internalXContent(XContentBuilder builder, Params params) throws IOException {
        if (filter != null) {
            filter.toXContent(builder, params);
        }
        return builder;