Set device features on device initialization

Summary:
1. Identify if device supports screenshots/screen recording when it is created.
2. Disable screen recording/screenshot buttons when they are not supported

Reviewed By: passy

Differential Revision: D34611133

fbshipit-source-id: 82ad2d67e4af482d9becf7995187667b5d99bc36

desktop/flipper-server-core/src/devices/ios/IOSDevice.tsx

@@ -36,6 +36,10 @@ export default class IOSDevice extends ServerDevice {
       title,
       os: 'iOS',
       icon: 'mobile',
+      features: {
+        screenCaptureAvailable: true,
+        screenshotAvailable: true,
+      },
     });
     this.buffer = '';
     this.iOSBridge = iOSBridge;
@@ -76,10 +80,6 @@ export default class IOSDevice extends ServerDevice {
     });
   }
 
-  async screenCaptureAvailable() {
-    return this.connected;
-  }
-
   async startScreenCapture(destination: string) {
     const recording = this.recording;
     if (recording) {