Fix ImGui assertions in built game UI (#753)

Author: Gopmyc

Sources/OvUI/include/OvUI/Core/UIManager.h

@@ -152,10 +152,10 @@ namespace OvUI::Core
 	private:
 		OvWindowing::Window& m_window;
 		OvTools::Eventing::ListenerID m_contentScaleChangedListener;
-		bool m_dockingState;
+		bool m_dockingState = false;
 		Styling::EStyle m_currentStyle;
-		float m_scale;
-		bool m_dpiAware;
+		float m_scale = 1.0f;
+		bool m_dpiAware = false;
 		bool m_refreshStyle = false;
 		Modules::Canvas* m_currentCanvas = nullptr;
 		std::unordered_map<std::string, ImFont*> m_fonts;

Sources/OvUI/src/OvUI/Panels/PanelUndecorated.cpp

@@ -11,22 +11,17 @@
 void OvUI::Panels::PanelUndecorated::_Draw_Impl()
 {
 	ImGui::PushStyleVar(ImGuiStyleVar_WindowPadding, { 0, 0 });
-	ImGui::PushStyleVar(ImGuiStyleVar_WindowMinSize, { 0, 0 });
+	ImGui::PushStyleVar(ImGuiStyleVar_WindowMinSize, { 1.0f, 1.0f });
 
 	if (ImGui::Begin(m_panelID.c_str(), nullptr, CollectFlags()))
 	{
-		ImGui::PopStyleVar(2);
-
 		Update();
-			
-		DrawWidgets();
 
-		ImGui::End();
-	}
-	else
-	{
-		ImGui::PopStyleVar(2);
+		DrawWidgets();
 	}
+
+	ImGui::End();
+	ImGui::PopStyleVar(2);
 }
 
 int OvUI::Panels::PanelUndecorated::CollectFlags()