Fix Vulkan example hang

When vkQueuePresentKHR or vkAcquireNextImageKHR return VK_SUBOPTIMAL_KHR, FramePresent will not be called because of

https://github.com/ocornut/imgui/blob/v1.92.9/examples/example_win32_vulkan/main.cpp#L321-L322

Making vkQueuePresentKHR never called and never releasing the current frame, hanging the app because g_SwapChainRebuild is currently only released in the WM_SIZE message https://github.com/ocornut/imgui/blob/v1.92.9/examples/example_win32_vulkan/main.cpp#L546-L560