add type existence check for explorer refresh

functions/private/Invoke-WinUtilExplorerUpdate.ps1

@@ -3,40 +3,35 @@ function Invoke-WinUtilExplorerUpdate {
     .SYNOPSIS
         Refreshes the Windows Explorer
     #>
-
     param (
         [string]$action = "refresh"
     )
 
     if ($action -eq "refresh") {
         Invoke-WPFRunspace -DebugPreference $DebugPreference -ScriptBlock {
-            # Send the WM_SETTINGCHANGE message to all windows
+            # Define the Win32 type only if it doesn't exist
+            if (-not ([System.Management.Automation.PSTypeName]'Win32').Type) {
                 Add-Type -TypeDefinition @"
 using System;
 using System.Runtime.InteropServices;
 public class Win32 {
     [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = false)]
     public static extern IntPtr SendMessageTimeout(
-        IntPtr hWnd,
-        uint Msg,
-        IntPtr wParam,
-        string lParam,
-        uint fuFlags,
-        uint uTimeout,
-        out IntPtr lpdwResult);
+        IntPtr hWnd, uint Msg, IntPtr wParam, string lParam,
+        uint fuFlags, uint uTimeout, out IntPtr lpdwResult);
 }
 "@
+            }
 
             $HWND_BROADCAST = [IntPtr]0xffff
             $WM_SETTINGCHANGE = 0x1A
             $SMTO_ABORTIFHUNG = 0x2
-            $timeout = 100
 
-            # Send the broadcast message to all windows
-            [Win32]::SendMessageTimeout($HWND_BROADCAST, $WM_SETTINGCHANGE, [IntPtr]::Zero, "ImmersiveColorSet", $SMTO_ABORTIFHUNG, $timeout, [ref]([IntPtr]::Zero))
+            [Win32]::SendMessageTimeout($HWND_BROADCAST, $WM_SETTINGCHANGE,
+                [IntPtr]::Zero, "ImmersiveColorSet", $SMTO_ABORTIFHUNG, 100,
+                [ref]([IntPtr]::Zero))
         }
     } elseif ($action -eq "restart") {
-        # Restart the Windows Explorer
         taskkill.exe /F /IM "explorer.exe"
         Start-Process "explorer.exe"
     }