[Settings] [VCM] Allow selecting a picture for VCM camera mute when running elevated (#24247)

* Fix the issue of not being able to select an image for VCM
Camera mute while PowerToys is running elevated.

* change the buffer size for Path and filename

* move DLL import to native methods file

* Adding comment to rember to move back to WinUI3
when it is fixed

* making Dll Import methods internal

* changes from comments

* fix new c# errors

* Remove async

src/settings-ui/Settings.UI/Helpers/NativeMethods.cs

@@ -44,6 +44,9 @@ namespace Microsoft.PowerToys.Settings.UI.Helpers
         [DllImport("shell32.dll")]
         internal static extern int SHGetPathFromIDListW(IntPtr pidl, IntPtr pszPath);
 
+        [DllImport("Comdlg32.dll", CharSet = CharSet.Unicode)]
+        internal static extern bool GetOpenFileName([In, Out] OpenFileName openFileName);
+
 #pragma warning disable CA1401 // P/Invokes should not be visible
         [DllImport("user32.dll")]
         public static extern bool ShowWindow(System.IntPtr hWnd, int nCmdShow);