Fix unit tests for event refactor

Author: mzschwartz5

packages/engine/Specs/Scene/I3SLayerSpec.js

@@ -275,8 +275,8 @@ describe("Scene/I3SLayer", function () {
     const testLayer = mockI3SProvider.layers[0];
 
     expect(testLayer.tileset).toBeDefined();
-    expect(testLayer.tileset.tileUnload._listeners.length).toEqual(1);
-    expect(testLayer.tileset.tileVisible._listeners.length).toEqual(1);
+    expect(testLayer.tileset.tileUnload._listeners.size).toEqual(1);
+    expect(testLayer.tileset.tileVisible._listeners.size).toEqual(1);
 
     expect(testLayer._rootNode).toBeDefined();
     expect(testLayer._rootNode._tile).toBe(testLayer.tileset._root);

packages/engine/Specs/Widget/CesiumWidgetSpec.js

@@ -1662,17 +1662,17 @@ describe(
         })
         .then(function () {
           const preMixinListenerCount =
-            preMixinDataSource.entities.collectionChanged._listeners.length;
+            preMixinDataSource.entities.collectionChanged._listeners.size;
           const postMixinListenerCount =
-            postMixinDataSource.entities.collectionChanged._listeners.length;
+            postMixinDataSource.entities.collectionChanged._listeners.size;
 
           widget = widget.destroy();
 
           expect(
-            preMixinDataSource.entities.collectionChanged._listeners.length,
+            preMixinDataSource.entities.collectionChanged._listeners.size,
           ).not.toEqual(preMixinListenerCount);
           expect(
-            postMixinDataSource.entities.collectionChanged._listeners.length,
+            postMixinDataSource.entities.collectionChanged._listeners.size,
           ).not.toEqual(postMixinListenerCount);
         });
     });