message: Fix potential NULL dereference if no draw is found rendering overlay
diff: @@ -5430,7 +5430,11 @@ ResourceId VulkanDebugManager::RenderOverlay(ResourceId texid, DebugOverlay over
  {
  rs->lineWidth = 1.0f;
  - if(m_pDriver->GetDeviceFeatures().fillModeNonSolid)
  + if(mainDraw == NULL)
  + {
  + // do nothing
  + }
  + else if(m_pDriver->GetDeviceFeatures().fillModeNonSolid)
  {
  rs->polygonMode = VK_POLYGON_MODE_LINE;
  }
  