IgxGrid: Multi-column sorting does not work if custom sortStrategy is used

[mkamiishi]

Description

In this sample(https://stackblitz.com/edit/angular-pjwndf-2xqznm?file=src/app/grid/grid-sorting-sample/grid-sorting-sample.component.html) ‘Fruit’ and ‘Company Name’ columns use a custom sortStrategy so that ‘Fruit’ column uses ‘fruitIndex’ column data and ‘Company Name’ column uses ‘companyIndex’ column data respectively when they are sorted.
Now when multi-column sorting is applied, for example, 1st sort by ‘Group’ column, 2nd sort by ‘Fruit’ column, and 3rd sort by ‘Company Name’ column, the 3rd sort does not work as expected.

• igniteui-angular version: 15.0.9
• browser: Chrome

Steps to reproduce

Run the sample:https://stackblitz.com/edit/angular-pjwndf-2xqznm?file=src/app/grid/grid-sorting-sample/grid-sorting-sample.component.html

Result

Multi-column sorting does not work as expected.

Expected result

Multi-column sorting works with a custom sortStrategy.

[hanastasov]

Please add Prs for 14.2.x, 15.0.x as well.