UI: Clean up AXAML code

* Remove unused namespaces
* Remove redundant attached property setters
* Use IsCheckedChanged in lieu of the obsolete Checked
* Optimize row & column definitions

src/Ryujinx/UI/Views/Settings/SettingsInputView.axaml

@@ -1,4 +1,4 @@
-<UserControl
+<UserControl
     x:Class="Ryujinx.Ava.UI.Views.Settings.SettingsInputView"
     xmlns="https://github.com/avaloniaui"
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
@@ -21,12 +21,7 @@
         <Border Classes="settings">
             <Panel
                 Margin="10">
-                <Grid>
-                    <Grid.RowDefinitions>
-                        <RowDefinition Height="Auto"/>
-                        <RowDefinition Height="*" />
-                        <RowDefinition Height="Auto" />
-                    </Grid.RowDefinitions>
+                <Grid RowDefinitions="Auto,*,Auto">
                     <views:InputView
                         Grid.Row="0"
                         Name="InputView" />