Nulled Payment Gateway Fees V2023.2 Nulled

Fixed - Minor code fixes for where it was not adding taxes where as admin you try to delete the fees or add new filed with values

fix php bug

Added - An option whether to make service fees as tax or not, which you can control from addon configuraion page
Fixed - Minor code fixes for where even though invoice is paid it was adding Service fees to existing invoice in admin panel

- Added PHP 8.1 Support