Apply changes to user code from the layout explorer embedded in IntelliJ

This feature request depends on the resolution of https://github.com/flutter/flutter-intellij/issues/4511.

Layout Explorer allows the user to play with different flex factor settings to understand layout issues in FlexBox-based widgets (e.g., Row and Column). However, it currently doesn't show the user how their code needs to be modified to fix a layout error. We have been exploring potential workflows to enable this. @raison00 has some mocks she share here.