Reduce memory usage of GeoGridTiler tests (#59921)

This PR further reduces the memory footprint of the
testGeoHashGridCircuitBreaker test such that only
0.26% of the randomized runs result in memory usage of between
500kb-1mb. where most of that those that are in that range
produce ~650kb of usage. Before, 3% of the runs would use
> 50mb of memory resulting in OOMs in CI

Closes #59853.

x-pack/plugin/spatial/src/test/java/org/elasticsearch/xpack/spatial/search/aggregations/bucket/geogrid/GeoGridTilerTests.java

@@ -465,9 +465,9 @@ public void testGeoTileGridCircuitBreaker() throws IOException {
     }
 
     private void testCircuitBreaker(GeoGridTiler tiler) throws IOException {
-        Polygon polygon = GeometryTestUtils.randomPolygon(false);
-        int precision = randomIntBetween(0, 5);
-        TriangleTreeReader reader = triangleTreeReader(polygon, GeoShapeCoordinateEncoder.INSTANCE);
+        Geometry geometry = GeometryTestUtils.randomPolygon(false);
+        int precision = randomIntBetween(0, 3);
+        TriangleTreeReader reader = triangleTreeReader(geometry, GeoShapeCoordinateEncoder.INSTANCE);
         MultiGeoShapeValues.GeoShapeValue value =  new MultiGeoShapeValues.GeoShapeValue(reader);
 
         List<Long> byteChangeHistory = new ArrayList<>();