clean up code style for the pr which fixed updating size issue on Android (https://github.com/iou90/react-native-autoheight-webview/pull/88)

autoHeightWebView/index.android.js

     const { height: oldHeight, width: oldWidth, source: prevSource, script: prevScript } = state;
     const { style } = props;
     const { source, script } = getUpdatedState(props, getBaseScript);
-    const height = style && style.height ? style.height : null;
-    const width = style && style.width ? style.width : null;
+    const height = style ? style.height : null;
+    const width = style ? style.width : null;
     if (source.html !== prevSource.html || source.uri !== prevSource.uri || script !== prevScript) {
       return {
         source,
     }
     if (isSizeChanged(height, oldHeight, width, oldWidth)) {
       return {
-        height: height ? height : oldHeight,
-        width: width ? width : oldWidth,
+        height: height || oldHeight,
+        width: width || oldWidth,
         isSizeChanged: true
       };
     }