Add support for Copilot Spaces

[stevehipwell]

GitHub has just announced that the Copilot Spaces API is now GA.

[ibrahimkarimeddin]

I’m a new contributor and would love to work on this feature if it’s available.

[gmlewis]

I’m a new contributor and would love to work on this feature if it’s available.

Thank you, @ibrahimkarimeddin! It's yours.
Please see CONTRIBUTING.md for helpful details while working on this feature.