Fix crash - check if backgroundColor is null before trying to fetch it in ViewProps isLayoutOnly

Summary:
Noticed while working in MobileHome with android device, when interacting with the Tasks change progress/priority components (MobileHomeTasksDetailsSelectorToken), which provides `borderRadius` style and `backgroundColor: ifSelected ? value : null`, and when `backgroundColor` is `null`, the line changed in this diff crashes (throwing the `NoSuchKeyException` at `ReadableNativeMap:110` [because of isNull check on `ReadableNativeMap:107`])

Changelog:
[Android][Fixed] - Fixed crash when using style borderRadius: any with backgroundColor: null

Reviewed By: JoshuaGross

Differential Revision: D27932828

fbshipit-source-id: 801b04c856ee9dc5a36bbf3e6e3d81de9b1e81a1

Author: Peter Laraia

ReactAndroid/src/main/java/com/facebook/react/uimanager/interfaces/ViewProps.java

@@ -258,7 +258,9 @@ public static boolean isLayoutOnly(ReadableMap map, String prop) {
         // Ignore if explicitly set to default opacity.
         return map.isNull(OPACITY) || map.getDouble(OPACITY) == 1d;
       case BORDER_RADIUS: // Without a background color or border width set, a border won't show.
-        if (map.hasKey(BACKGROUND_COLOR) && map.getInt(BACKGROUND_COLOR) != Color.TRANSPARENT) {
+        if (map.hasKey(BACKGROUND_COLOR)
+            && !map.isNull(BACKGROUND_COLOR)
+            && map.getInt(BACKGROUND_COLOR) != Color.TRANSPARENT) {
           return false;
         }
         if (map.hasKey(BORDER_WIDTH)