fix: Server error while submitting PO/ PI

[IamSaiyyamChhetri]

• covers 254, 255 and 259

[IamSaiyyamChhetri]

• This Covers issue no. : Server Error while submitting a Purchase Order  #254 Server error while submitting Purchase Invoice #255 and Server Error if 'Apply Tax Withholding Catergory' checkbox is checked while creating Purchase Order & Purchase Invoice #259
• Due to Server Error if 'Apply Tax Withholding Catergory' checkbox is checked while creating Purchase Order & Purchase Invoice #259 error was throwing in Server Error while submitting a Purchase Order  #254 Server error while submitting Purchase Invoice #255
• When " Apply Tax Withholding Amount" Checkbox is checked then the error was generating.