Column group orderIndex not restored when loading saved state

[zstoyanova9]

Description

The Grid's loadState() method does not restore the orderIndex of column groups (kendo-grid-column-group) correctly. Although the column group's order is correctly saved via currentState, it is not reapplied when loading the state afterwards. This causes column groups to have an incorrect order instead of maintaining the saved reordered position.

Steps To Reproduce

1. Open the following StackBlitz example - https://stackblitz.com/edit/angular-2nwrn7db-2wkwjsdc
2. Move the "Product Name" column between "Category" and "Unit Price".
3. Click "Save State".
4. Reload the page.
5. Click "Load State".
6. Observe how the "Test" column group appears at the beginning with orderIndex: 0 instead of orderIndex: 4 as it was before.

Actual Behavior

Column groups appear in an incorrect order after loadState(), regardless of their order when the state was saved.

Expected Behavior

Column groups should restore to the same position they were in before the state was saved.