Set RadioButton background transparent by default (#13)

Author: imalcolm1

src/Esri.Calcite.Maui/Resources/Styles/Styles.xaml

@@ -346,6 +346,7 @@
     </Style>
 
     <Style TargetType="RadioButton" x:Key="CalciteRadioButtonStyle">
+        <Setter Property="Background" Value="Transparent"/>
         <Setter Property="TextColor" Value="{AppThemeBinding Light={x:DynamicResource CalciteText1LightColor}, Dark={x:DynamicResource CalciteText1DarkColor}}" />
         <Setter Property="ca:CalciteResourceHelper.Color" Value="{AppThemeBinding Light={x:DynamicResource CalciteBrandLightColor}, Dark={x:DynamicResource CalciteBrandDarkColor}}" />
         <Setter Property="ca:CalciteResourceHelper.Color2" Value="White" />