Error when sorting by invisible property/column

[jagrodal]

To reproduce:

1. Go to the column toggling example: https://swimlane.github.io/ngx-datatable/#/toggle
2. Sort by name
3. Toggle the visibility of the name column =>

chunk-DTGLECY5.js:7 ERROR TypeError: l.compareFn is not a function
at chunk-DTGLECY5.js:10:43066
at Array.sort ()
at Ks (chunk-DTGLECY5.js:10:42971)
at An.sortInternalRows (chunk-DTGLECY5.js:10:83030)
at An.translateColumns (chunk-DTGLECY5.js:10:77240)
at Object.next (chunk-DTGLECY5.js:10:77023)
at oa.next (chunk-DTGLECY5.js:3:3107)
at Ln._next (chunk-DTGLECY5.js:3:2790)
at Ln.next (chunk-DTGLECY5.js:3:2517)
at chunk-DTGLECY5.js:3:14232