Applying logic to button Make Copy

       const lineIsCopied = () => {
            let lineNumber = opportunity.getCurrentSublistValue({
                sublistId: 'item',
                fieldId: 'line'
            });

            if (lineNumber) {
                //linenumber is existing this means line is not a copy
                return false;
            } else {
                //linenumber is empty this mean line is a copy
                return true;
            }
        };