misc: revert high-contrast Theme feat.

src/Semi.Avalonia/Controls/DataValidationErrors.axaml

@@ -2,6 +2,7 @@
     xmlns="https://github.com/avaloniaui"
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
     xmlns:collections="clr-namespace:System.Collections;assembly=netstandard">
+    <!--  Add Resources Here  -->
     <ControlTheme x:Key="{x:Type DataValidationErrors}" TargetType="DataValidationErrors">
         <Setter Property="Template">
             <ControlTemplate TargetType="DataValidationErrors">