Add an existence check for debug callback in createCommandBuffers_impl.

Author: achalpandeyy

src/nbl/video/CVulkanLogicalDevice.cpp

@@ -177,10 +177,12 @@ bool CVulkanLogicalDevice::createCommandBuffers_impl(IGPUCommandPool* cmdPool, I
     {
         for (uint32_t i = 0u; i < count; ++i)
         {
+            const auto* debugCb = m_physicalDevice->getDebugCallback();
+
             outCmdBufs[i] = core::make_smart_refctd_ptr<CVulkanCommandBuffer>(
                 core::smart_refctd_ptr<ILogicalDevice>(this), level, vk_commandBuffers[i],
                 core::smart_refctd_ptr<IGPUCommandPool>(cmdPool),
-                core::smart_refctd_ptr<system::ILogger>(m_physicalDevice->getDebugCallback()->getLogger()));
+                debugCb ? core::smart_refctd_ptr<system::ILogger>(debugCb->getLogger()) : nullptr);
         }
 
         return true;