Canceling the closing event is not working

[os-lmo]

Describe the bug
If we enable the Cancel arg in the Closing event, Avalonia is ignoring it and the application closes.
It only happens in 0.10.999-cibuild0017786-beta version

To Reproduce
Steps to reproduce the behavior:

1. In MacOS, build the demo available here
2. Open the demo
3. Go to the native menu and choose "Quit" (or Cmd + Q)
4. The application closes, and it shouldn't

Expected behavior
The application should not close, since we are explicitly canceling the close.

Screenshots
We are canceling the close event but it seems not having effect

Desktop (please complete the following information):

[maxkatz6]

Window is not closing, but whole app is shutting down. It's a special behavior of macos, which doesn't even tried to close windows at this point.
If you need to cancel app shutting down - there is ShutdownRequested event.
Although as I see from other ticket, there is a problem too #7389

[heldergoncalves92]

Is this a new behavior that changed on purpose? Since versions equal and below 0.10.11 do not have that behavior, and allowed to cancel closing at this point.

[maxkatz6]

Seems like I was wrong, and now we manually call Close on all windows, when shutdown is requested.
So only #7400 issue was left.