vulkan/wsi/wayland: Handle unset present_mode
What does this MR do and why?
When IMMEDIATE present mode was introduced, our handling of VlSurfacePresentModeCompatibility changed - we now crash if no VkSurfacePresentModeEXT is chained up, whereas before we would return the full count of available modes.
Marked as draft, because while this restores previous not-crashing behaviour, there's some contention as to whether we should do that or consider this a bug in vulkan-tools: https://github.com/KhronosGroup/Vulkan-Tools/issues/846
cc @emersion