vulkan: Set initial layout to undefined
Having the initial layout set to VK_IMAGE_LAYOUT_GENERAL causes issues when going from the final layout to the initial layout since the image layout is expected to be the general layout. Setting the initial layout to undefined doesn't have this restriction.
This issue can be found with GSK_RENDERER=vulkan VK_INSTANCE_LAYERS=VK_LAYER_KHRONOS_validation gtk4-demo
.