[V12] MacOS Tray Icon Adjustments

[drasticactions]

Is your feature request related to a problem? Please describe.

As part of #19628, I had made changes to the Tray Icon logic for flooring the calculations of the image width and height, so it would appear sharper and not blurry. I did it this way as to try and "split the difference" between making a larger change and risking regression (People wondering why their icons look different, worse, etc).

For Avalonia 12, we can try and make those larger changes to both remove the scaling and give more options to NSStatusBar items that MacOS supports, but we don't expose.

Describe the solution you'd like

• Create an updated API surface for allowing handling TrayIcon generation and more of the NSStatusBar API surfaces, including setting the size of the box (Square or Variable), and the icons Width and Height directly.
• Have a fallback to keep the existing logic if a user never changes from the original defaults from Avalonia 11.x

Describe alternatives you've considered

No response

Additional context

No response