Update ContentPage.cs

Author: kubaflo

src/Controls/src/Core/ContentPage/ContentPage.cs

@@ -1,7 +1,6 @@
 #nullable disable
 
 using System;
-using System.ComponentModel;
 using Microsoft.Maui.Graphics;
 using Microsoft.Maui.HotReload;
 using Microsoft.Maui.Layouts;