Review and update tutorial on 'Layouts in Flutter' page

[CivanDogan]

Page URL: https://docs.flutter.dev/ui/layout Page source: https://github.com/flutter/website/tree/master/src/docs/development/ui/layout/index.md

Description of issue: This tutorial is awesome but probably outdated. Sizing Widgets is not working as in the example. Setting flex :2 not makes the images get bigger vertically . Thank you

[CivanDogan]

It's because of the Image.asset because Expanded take up space as in tutorial.