[UI] Fixed issues with ImGui on Vulkan and few ASAN issues related to ImGui

- Simplified handling of notifications to faster version with ranges
- Removed usage of STB sprintf on checked due to ASAN violation
- Draw ImGui windows only when they're not in close_pending state

src/xenia/ui/vulkan/vulkan_immediate_drawer.cc

@@ -223,10 +223,7 @@ void VulkanImmediateDrawer::Begin(UIDrawContext& ui_draw_context,
       continue;
     }
     DestroyTextureResource(it->first);
-    if (std::next(it) != textures_deleted_.end()) {
-      *it = textures_deleted_.back();
-    }
-    textures_deleted_.pop_back();
+    it = textures_deleted_.erase(it);
   }
 
   // Release upload buffers for completed texture uploads.