Windows: Disable exclusive fullscreen mode

[白山風露]

I was working on a fullscreen implementation at zed-industries/zed#9728 and ran into a problem where it would automatically go into exclusive fullscreen mode, and it needed to use VK_EXT_full_screen_exclusive to fix this.

kazatsuyu@662787b
This is my quick implementation and I have confirmed that it works, but I don't know much about blade internals and don't have a lot of knowledge of Vulkan, so I would need to consult with you on how to implement it.

[白山風露]

Sorry, sent by mistake before writing details

[Dzmitry Malyshau]

Thank you for drafting this!
I was thinking that we'd add a field to the surface config:

struct SurfaceConfig {
...
  pub allow_exclusive_fullscreen: bool,
}

And then in Vulkan backend this flag would drive the use of VK_EXT_full_screen_exclusive extension, if present