[Maps] fix blended layer aggregation error when using composite aggregation (#72759) (#72945)

Author: nreese

x-pack/plugins/maps/public/classes/sources/es_geo_grid_source/es_geo_grid_source.js

@@ -161,7 +161,6 @@ export class ESGeoGridSource extends AbstractESAggSource {
                   bounds: makeESBbox(bufferedExtent),
                   field: this._descriptor.geoField,
                   precision,
-                  size: DEFAULT_MAX_BUCKETS_LIMIT,
                 },
               },
             },