adds error handler when caching a video file from the picker

Author: Miguel Ruivo

packages/image_picker/ios/Classes/ImagePickerPlugin.m

@@ -247,12 +247,21 @@ - (void)imagePickerController:(UIImagePickerController *)picker
           [NSURL fileURLWithPath:[NSTemporaryDirectory() stringByAppendingPathComponent:fileName]];
 
       if ([[NSFileManager defaultManager] isReadableFileAtPath:[videoURL path]]) {
-        [[NSFileManager defaultManager] copyItemAtURL:videoURL toURL:destination error:nil];
+        NSError *error;
+        [[NSFileManager defaultManager] copyItemAtURL:videoURL toURL:destination error:&error];
+        if (error) {
+          self.result([FlutterError errorWithCode:@"flutter_image_picker_copy_video_error"
+                                          message:@"Could not cache the video file."
+                                          details:nil]);
+          self.result = nil;
+          return;
+        }
         videoURL = destination;
       }
     }
     self.result(videoURL.path);
     self.result = nil;
+
   } else {
     UIImage *image = [info objectForKey:UIImagePickerControllerEditedImage];
     if (image == nil) {