Library: Port 'View Switcher' to Python

[UrtsiSantsi]

[UrtsiSantsi]

Some observations:

1. This demo opens a window even for JavaScript, but the Python window size is different. Vala has the same size as Python.
2. For me the Python preview never starts the first time I press 'Run' (it gives me some errors), only the second for all demos. Then it works as expected. Vala and Rust start don't have such problems. For this demo however I get: then it works, but the window can't be closed. Vala preview can be closed normally.

[imhemish]

@theCapypara I suggest using a .get_ancestor method on the button as button is contained inside row. See https://github.com/workbenchdev/demos/pull/109#issuecomment-1962976016 This would ensure we aren't creating a reference to row in a python object

[sonnyp]

HJo I just realized this one is still opened against Workbench.

Ok I'll close this one instead. Sorry for the noise