CmdPal: A different approach to bookmarking scripts, exes (try 2) (#40758)

_⚠️ targets #40427_ 

This is a different approach to #39059 that I was thinking about like a
month ago. It builds on the work from the rejuv'd run page (#39955) to
process the bookmark as an exe/path/url automatically.

I need to cross-check this with #39059 - I haven't cached that back in
since I got back from leave. I remember thinking that I wanted to try
this approach, but wasn't sure if it was right. More than anything, I
want to get it off my local PC and out for discussion

* We don't need to manually store the type anymore. 
* breaking change: paths with a space do need to be wrapped in spaces

closes #38700

----

I accidentally destroyed #40430 with a fat-finger merge from #40427 into
it. This resurrects that PR

src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.Shell/FallbackExecuteItem.cs

@@ -89,7 +89,7 @@ internal sealed partial class FallbackExecuteItem : FallbackCommandItem, IDispos
             return;
         }
 
-        ShellListPage.ParseExecutableAndArgs(searchText, out var exe, out var args);
+        ShellHelpers.ParseExecutableAndArgs(searchText, out var exe, out var args);
 
         // Check for cancellation before file system operations
         cancellationToken.ThrowIfCancellationRequested();
@@ -191,7 +191,7 @@ internal sealed partial class FallbackExecuteItem : FallbackCommandItem, IDispos
             return false;
         }
 
-        ShellListPage.ParseExecutableAndArgs(searchText, out var exe, out var args);
+        ShellHelpers.ParseExecutableAndArgs(searchText, out var exe, out var args);
         var exeExists = ShellListPageHelpers.FileExistInPath(exe, out var fullExePath);
         var pathIsDir = Directory.Exists(exe);