### Elasticsearch Version

8.9.0

### Installed Plugins

_No response_

### Java Version

_bundled_

### OS Version

all

### Problem Description

In https://github.com/elastic/elasticsearch/pull/96953 we added support for a much more memory efficient algorithm that relies on the time-ordering and grouping provided by the time-series aggregation in TSDB. However, this work only covered the data nodes, and the reduce phase in the coordinating nodes that merges geo_lines does not take this into account, leading to unexpected truncation of long geo_lines.

### Steps to Reproduce

Easiest to reproduce by setting the shard size small, loading very long geolines that will be composed of many data points over many shards, and then setting the geo_line aggregation size to a small size. The final lines will not include the two end points as they should, but be truncated.

### Logs (if relevant)

_No response_
x-pack/plugin/spatial/src/main/java/org/elasticsearch/xpack/spatial/search/aggregations/InternalGeoLine.java
return super.equals(obj)
            && Arrays.equals(line, that.line)
            && Arrays.equals(sortVals, that.sortVals)
            && Objects.equals(complete, that.complete)
            && Objects.equals(includeSorts, that.includeSorts)
            && Objects.equals(sortOrder, that.sortOrder)
            && Objects.equals(size, that.size);
    }
    @Override
    public Map<String, Object> geoJSONGeometry() {
        final List<double[]> coordinates = new ArrayList<>();
        for (int i = 0; i < line.length; i++) {
            int x = (int) (line[i] >> 32);
            int y = (int) line[i];
            coordinates.add(
                new double[] { roundDegrees(GeoEncodingUtils.decodeLongitude(x)), roundDegrees(GeoEncodingUtils.decodeLatitude(y)) }
            );
        }
        final Map<String, Object> geoJSON = new HashMap<>();
        if (coordinates.size() == 1) {
            geoJSON.put("type", "Point");
            geoJSON.put("coordinates", coordinates.get(0));
        } else {
            geoJSON.put("type", "LineString");
            geoJSON.put("coordinates", coordinates.toArray());
        }
        return geoJSON;
    }
}