RFC: vulkan/swapchain: add swapchain_params.disallow_pass_through_csp

There are cases where color is set externally and we don't want/need Vulkan/WSI managing it itself. Examples would be DRM output or Wayland where wp_color_management_surface_v1 is used outside of libplacebo.

In other cases it's likely better to set swapchain colorspace in libplacebo itself.