Modify DNS ComboBox

- Replaced "Default" with "Custom"
- Set Default Dropdown Content to applied option or "Custom" if not in the list.
- saves custom IPs on multiple adapters
> If user sets DNS to Cloudflare and runs the tweaks but wants to undo it before he closed the script he can select "custom" and run it to apply the saved addresses

scripts/main.ps1

@@ -434,6 +434,8 @@ $sync["CheckboxFilter"].Add_TextChanged({
         $label.Visibility = "Collapsed"}
 })
 
+Get-WinUtilDNS
+
 # Define event handler for button click
 $sync["SettingsButton"].Add_Click({
     Write-Debug "SettingsButton clicked"