[PTRun]Fix accent on title bar bleed into UI (#33046)

* [PTRun]Fix accent on title bar bleed into UI

* Fix XAML style

src/modules/launcher/PowerLauncher/MainWindow.xaml

@@ -45,6 +45,11 @@
             Grid.Row="0"
             Padding="12,4,12,3">
             <local:LauncherControl x:Name="SearchBox" />
+            <Border.Background>
+                <!--  Setting the background of the search bar to fix https://github.com/microsoft/PowerToys/issues/30206  -->
+                <!--  The title bar accent would bleed if the option to "Show accent color on title bars and windows borders" is enabled on Windows  -->
+                <SolidColorBrush Opacity="1" Color="{DynamicResource ApplicationBackgroundColor}" />
+            </Border.Background>
         </Border>
 
         <!--  Have to use a Grid instead of a StackPanel for scrolling to work?  -->