DataTable: hide column after reordering columns throws exception

[Yousefjb]

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[x] bug report
[ ] feature request
[ ] support request => Please do not submit support request here, instead see https://forum.primefaces.org/viewforum.php?f=57

Plunkr Case (Bug Reports)
tried to use plunkr but it refused to render

Current behavior
I can't toggle columns when reorderableColumns props is enabled and the columns has been reordered

Expected behavior
I can toggle columns when they are reodered

Minimal reproduction of the problem with instructions

getColumns() {
        let columns = React.Children.toArray(this.props.children);
        
        if(this.props.reorderableColumns && this.state.columnOrder) {
            let orderedColumns = [];
            for(let columnKey of this.state.columnOrder) {
                // <-- here
                // should check if findColumnByKey return column or undefined
                orderedColumns.push(this.findColumnByKey(columns, columnKey));
            }
                        
            return orderedColumns;
        }
        else {
            return columns;
        }
    }

Please tell us about your environment:

• React version:
  ^16.6.3

• PrimeReact version:
  ^2.0.0

• Browser: [all | Chrome XX | Firefox XX | IE XX | Safari XX | Mobile Chrome XX | Android X.X Web Browser | iOS XX Safari | iOS XX UIWebView | iOS XX WKWebView ]
  all

• Language: [all | TypeScript X.X | ES6/7 | ES5]
  ES6