jme3-examples: PBRTerrainTest - typo in the ambient light color setting

[capdevon]

https://github.com/jMonkeyEngine/jmonkeyengine/blob/master/jme3-examples/src/main/java/jme3test/terrain/PBRTerrainTest.java#L355

    private void setUpLights() {
        LightProbe probe = (LightProbe) assetManager.loadAsset("Scenes/LightProbes/quarry_Probe.j3o");

        probe.setAreaType(LightProbe.AreaType.Spherical);
        probe.getArea().setRadius(2000);
        probe.getArea().setCenter(new Vector3f(0, 0, 0));
        rootNode.addLight(probe);

        directionalLight = new DirectionalLight();
        directionalLight.setDirection((new Vector3f(-0.3f, -0.5f, -0.3f)).normalize());
        directionalLight.setColor(ColorRGBA.White);
        rootNode.addLight(directionalLight);

        ambientLight = new AmbientLight();
        directionalLight.setColor(ColorRGBA.White); //<- It should be ambientLight.setColor(ColorRGBA.White);
        rootNode.addLight(ambientLight);
    }