Merge pull request #12837 from mike-000/getDataAtPixel

forEachLayerAtPixel return null for unsupported layer types

src/ol/renderer/Layer.js

@@ -130,7 +130,7 @@ class LayerRenderer extends Observable {
    *    returned, and empty array will be returned.
    */
   getDataAtPixel(pixel, frameState, hitTolerance) {
-    return abstract();
+    return null;
   }
 
   /**