CmdPal: Update the alias tags, before triggering the UI to change (#38172)

Yea, this one hurts. Pretty obviously, we're sending the PropChanged
_before_ the `Tags` are actually updated.

Noticed on 0.0.16+ builds

Author: zadjii-msft

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/TopLevelViewModel.cs

@@ -207,12 +207,11 @@ private void UpdateTags()
             tags.Add(new Tag() { Text = Alias.SearchPrefix });
         }
 
-        PropChanged?.Invoke(this, new PropChangedEventArgs(nameof(Tags)));
-
         DoOnUiThread(
             () =>
             {
                 ListHelpers.InPlaceUpdateList(Tags, tags);
+                PropChanged?.Invoke(this, new PropChangedEventArgs(nameof(Tags)));
             });
     }