misc: chore: cleanup 2 accidental xml namespaces

src/Ryujinx/UI/Views/Main/MainMenuBarView.axaml

@@ -4,10 +4,8 @@
     xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
     xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
     xmlns:ext="clr-namespace:Ryujinx.Ava.Common.Markup"
-    xmlns:uih="clr-namespace:Ryujinx.UI.Common.Helper"
     mc:Ignorable="d"
     xmlns:viewModels="clr-namespace:Ryujinx.Ava.UI.ViewModels"
-    xmlns:helper="clr-namespace:Ryujinx.UI.Common.Helper;assembly=Ryujinx.UI.Common"
     x:DataType="viewModels:MainWindowViewModel"
     x:Class="Ryujinx.Ava.UI.Views.Main.MainMenuBarView">
     <Design.DataContext>