vulkan: Don't attempt to free 0 command buffers
vkFreeCommandBuffers can't be called with commandBufferCount set to 0.
This issue can be found with GSK_RENDERER=vulkan VK_INSTANCE_LAYERS=VK_LAYER_KHRONOS_validation gtk4-demo.
vkFreeCommandBuffers can't be called with commandBufferCount set to 0.
This issue can be found with GSK_RENDERER=vulkan VK_INSTANCE_LAYERS=VK_LAYER_KHRONOS_validation gtk4-demo.