update(launch screen): Add iPhone X launch screens (#5163)

apps/app/App_Resources/iOS/Assets.xcassets/LaunchImage.launchimage/Contents.json

@@ -1,5 +1,23 @@
 {
   "images" : [
+    {
+      "extent" : "full-screen",
+      "idiom" : "iphone",
+      "subtype" : "2436h",
+      "filename" : "Default-1125h.png",
+      "minimum-system-version" : "11.0",
+      "orientation" : "portrait",
+      "scale" : "3x"
+    },
+    {
+      "orientation" : "landscape",
+      "idiom" : "iphone",
+      "extent" : "full-screen",
+      "filename" : "Default-Landscape-X.png",
+      "minimum-system-version" : "11.0",
+      "subtype" : "2436h",
+      "scale" : "3x"
+    },
     {
       "extent" : "full-screen",
       "idiom" : "iphone",