Demo: Assets Browser: use correct axis for layout computation, to allow making items non-square. (#8207)

imgui_demo.cpp

@@ -10175,7 +10175,7 @@ struct ExampleAssetsBrowser
         }
 
         ImGuiIO& io = ImGui::GetIO();
-        ImGui::SetNextWindowContentSize(ImVec2(0.0f, LayoutOuterPadding + LayoutLineCount * (LayoutItemSize.x + LayoutItemSpacing)));
+        ImGui::SetNextWindowContentSize(ImVec2(0.0f, LayoutOuterPadding + LayoutLineCount * (LayoutItemSize.y + LayoutItemSpacing)));
         if (ImGui::BeginChild("Assets", ImVec2(0.0f, -ImGui::GetTextLineHeightWithSpacing()), ImGuiChildFlags_Borders, ImGuiWindowFlags_NoMove))
         {
             ImDrawList* draw_list = ImGui::GetWindowDrawList();