Link to TitleBar Experimental Samples (#1559)

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## Description
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Add link to TitleBar Experimental samples:

## Screenshots (if appropriate):

![image](https://github.com/microsoft/WinUI-Gallery/assets/7976322/398b051e-9d15-421b-96df-c430338d681d)

WinUIGallery/ControlPages/TitleBarPage.xaml

@@ -26,6 +26,17 @@
     </Page.Resources>
 
     <StackPanel>
+        <InfoBar IsOpen="True" IsClosable="False" Margin="0,12">
+            <TextBlock>
+                TitleBar control is now available in <Hyperlink NavigateUri="https://learn.microsoft.com/windows/apps/windows-app-sdk/experimental-channel#required-c-project-changes-for-16-experimental1">Experimental</Hyperlink>!
+
+                Preview samples for TitleBar at <Hyperlink NavigateUri="https://github.com/microsoft/WinUI-Gallery/blob/feature/TitleBarExperimental/WinUIGallery/ControlPages/TitleBarPage.xaml">feature/TitleBarExperimental</Hyperlink>
+            </TextBlock>
+
+        </InfoBar>
+
+
+
         <local:ControlExample HeaderText="Default titlebar (when no user defined titlebar is set)"
                               CSharpSource="Window\TitleBar\TitleBarSample2.txt">
             <local:ControlExample.Example>