Added proper description to image related permissions on iOS

[Khosbayar]

Overview

• Added NSPhotoLibraryAddUsageDescription,
• Needed to give more accurate description for below permissions:

      <key>NSPhotoLibraryUsageDescription</key>
  <string>App requires access to the photo library.</string>
  <key>NSCameraUsageDescription</key>
  <string>App requires access to the camera.</string>
  <key>NSMicrophoneUsageDescription</key>
  <string>App does not require access to the microphone.</string>
  <key>NSPhotoLibraryAddUsageDescription</key>
  <string>App requires write access to the photo library.</string>