Properly feature detect for orientation APIs (#4875)

- Prefer to use hasOwnProperty() over truthy check

src/utils/agent/Agent.js

@@ -89,13 +89,17 @@ export default class Agent {
      * @returns {boolean} true in portrait mode
      */
     isPortrait() {
-        const { screen, orientation } = this.window;
+        const { screen } = this.window;
+        const hasScreenOrientation = screen && Object.prototype.hasOwnProperty.call(screen, 'orientation');
+        const hasWindowOrientation = Object.prototype.hasOwnProperty.call(this.window, 'orientation');
 
-        if (screen && screen.orientation) {
+        if (hasScreenOrientation) {
             return screen.orientation.type.includes('portrait');
-        } else if (orientation) {
+        } else if (hasWindowOrientation) {
             // Use window.orientation API if available (e.g. Safari mobile)
             // which returns [-90, 0, 90, 180] based on device orientation.
+            const { orientation } = this.window;
+
             return Math.abs(orientation / 90) % 2 === 0;
         } else {
             return this.window.innerWidth < this.window.innerHeight;