Fix FakeMouseEvent class after jsdom implemented missing MouseEvent properties

Previously MouseEvent in jsdom didn't have attributes like pageX,pageY.
Now it supports it, but these properties only have getters and not
setters. That's why we are overriding these properties with
Object.defineProperties to fix the errors.

Author: canova

src/test/fixtures/utils.js

@@ -73,24 +73,35 @@ type FakeMouseEventInit = $Shape<{
 }>;
 
 class FakeMouseEvent extends MouseEvent {
-  offsetX: number;
-  offsetY: number;
-  pageX: number;
-  pageY: number;
-  x: number;
-  y: number;
-
   constructor(type: string, values: FakeMouseEventInit) {
     const { pageX, pageY, offsetX, offsetY, x, y, ...mouseValues } = values;
     super(type, (mouseValues: any));
 
-    Object.assign(this, {
-      offsetX: offsetX || 0,
-      offsetY: offsetY || 0,
-      pageX: pageX || 0,
-      pageY: pageY || 0,
-      x: x || 0,
-      y: y || 0,
+    Object.defineProperties(this, {
+      offsetX: {
+        value: offsetX || 0,
+        writable: false,
+      },
+      offsetY: {
+        value: offsetY || 0,
+        writable: false,
+      },
+      pageX: {
+        value: pageX || 0,
+        writable: false,
+      },
+      pageY: {
+        value: pageY || 0,
+        writable: false,
+      },
+      x: {
+        value: x || 0,
+        writable: false,
+      },
+      y: {
+        value: y || 0,
+        writable: false,
+      },
     });
   }
 }