TreeGraph() for the playground

[Xiaoy312]

What would you like to be added:

TreeGraph() for the playground, to get a debug dump of the visual tree
with this implemention of describe function:
https://github.com/unoplatform/uno.toolkit.ui/blob/3.0.0/src/Uno.Toolkit.UI/Helpers/VisualTreeHelperEx.cs#L172
which contains most relevant informations about layouting.
Which we can directly dump the output to a TextBlock, to the console(doesnt look pretty, and dotnet.js:123 are not good for copying), or even set the clipboard.

Why is this needed:

Generical QoL to easily access info without needing to start a custom project.