CmdPal: Move the OpenContextMenuMessage into the UI project (#40791)

I just blindly moved all the messages. But _this_ one really makes more
sense as a UI message. It's got framework elements. It us used to
actually open a UI element. The whole thing is very UI specific.

re: #40113

src/modules/cmdpal/Microsoft.CmdPal.UI/Controls/CommandBar.xaml.cs

@@ -5,6 +5,7 @@
 using CommunityToolkit.Mvvm.Messaging;
 using Microsoft.CmdPal.Core.ViewModels;
 using Microsoft.CmdPal.Core.ViewModels.Messages;
+using Microsoft.CmdPal.UI.Messages;
 using Microsoft.CmdPal.UI.Views;
 using Microsoft.UI.Xaml;
 using Microsoft.UI.Xaml.Controls;

src/modules/cmdpal/Microsoft.CmdPal.UI/Controls/ContextMenu.xaml.cs

@@ -5,6 +5,7 @@
 using CommunityToolkit.Mvvm.Messaging;
 using Microsoft.CmdPal.Core.ViewModels;
 using Microsoft.CmdPal.Core.ViewModels.Messages;
+using Microsoft.CmdPal.UI.Messages;
 using Microsoft.UI.Input;
 using Microsoft.UI.Xaml;
 using Microsoft.UI.Xaml.Controls;
@@ -38,6 +39,9 @@ public sealed partial class ContextMenu : UserControl,
 
     public void Receive(OpenContextMenuMessage message)
     {
+        ViewModel.FilterOnTop = message.ContextMenuFilterLocation == ContextMenuFilterLocation.Top;
+        ViewModel.ResetContextMenu();
+
         UpdateUiForStackChange();
     }
 

src/modules/cmdpal/Microsoft.CmdPal.UI/Controls/SearchBar.xaml.cs

@@ -6,6 +6,7 @@ using CommunityToolkit.Mvvm.Messaging;
 using CommunityToolkit.WinUI;
 using Microsoft.CmdPal.Core.ViewModels;
 using Microsoft.CmdPal.Core.ViewModels.Messages;
+using Microsoft.CmdPal.UI.Messages;
 using Microsoft.CmdPal.UI.Views;
 using Microsoft.UI.Dispatching;
 using Microsoft.UI.Input;