refactor: leverage ClipToBounds instead of a custom converter

Set ClipToBounds="True" instead of using the `BorderClipConverter` in the Button ControlTemplate to prevent child elements from rendering outside the template boundaries.

Author: corvinsz

src/MaterialDesignThemes.Wpf/Themes/MaterialDesignTheme.PopupBox.xaml

@@ -17,7 +17,7 @@
     <Setter Property="Template">
       <Setter.Value>
         <ControlTemplate TargetType="{x:Type Button}">
-          <Grid x:Name="rootGrid">
+          <Grid ClipToBounds="True">
             <VisualStateManager.VisualStateGroups>
               <VisualStateGroup Name="CommonStates">
                 <VisualStateGroup.Transitions>
@@ -57,14 +57,7 @@
                       ContentTemplateSelector="{TemplateBinding ContentTemplateSelector}"
                       Feedback="{TemplateBinding Foreground, Converter={x:Static converters:BrushRoundConverter.Instance}}"
                       Focusable="False"
-                      SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" >
-              <wpf:Ripple.Clip>
-                <MultiBinding Converter="{x:Static converters:BorderClipConverter.Instance}">
-                  <Binding ElementName="rootGrid" Path="ActualWidth" />
-                  <Binding ElementName="rootGrid" Path="ActualHeight" />
-                </MultiBinding>
-              </wpf:Ripple.Clip>
-            </wpf:Ripple>
+                      SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" />
           </Grid>
         </ControlTemplate>
       </Setter.Value>