Fix ng pipe and TemplateRef for tables with invisible columns

[khicks]

When applying Angular features like pipe and TemplateRef on a table with invisible columns, there is a discrepancy between the column definition and the resulting HTML. The library makes reference to the resulting HTML when modifying the table and assumes invisible columns are present in the DOM.

This proposed fix ensures that only visible columns are considered when deciding which column(s) to modify when applying pipe transforms or templates.

[khicks]

Fixes issue #1721.

[shanmukhateja]

Can you add a unit test for this so we don't run into it in the future?

[shanmukhateja]

@khicks any update on this?

[shanmukhateja]

Closing in favor of https://github.com/l-lin/angular-datatables/pull/1725