Remove two redundant lines of code setting io.DisplaySize in ImGuiLayer.cpp

[littlecaca]

Hazel/Hazel/src/Hazel/ImGui/ImGuiLayer.cpp

Lines 100 to 101 in 1feb705

	Application& app = Application::Get();
	io.DisplaySize = ImVec2((float)app.GetWindow().GetWidth(), (float)app.GetWindow().GetHeight());

This is redundant because the "ImGui_ImplGlfw_NewFrame();" has done this work. That is in

Hazel/Hazel/src/Hazel/ImGui/ImGuiLayer.cpp

Lines 89 to 91 in 1feb705

	ImGui_ImplOpenGL3_NewFrame();
	ImGui_ImplGlfw_NewFrame();
	ImGui::NewFrame();

And the definition of ImGui_ImplGlfw_NewFrame() is in:https://github.com/TheCherno/imgui/blob/3cf61f67de73153e29e0c26f23d80edbaf120a3d/examples/imgui_impl_glfw.cpp#L473-L477

So, I removed them. Not confirmed its working state.