[Elements]: autoGenerate does not override columns declared in markup

[RivaIvanova]

Description

When set to true, the autoGenerate property in igniteui-angular overrides all columns declared through code or in markup as stated in the API docs.
When used in WebComponents/React/Blazor the declared columns persist.

• "igniteui-webcomponents-grids": "4.8.0",
• "igniteui-react-grids": "18.6.0",
• "IgniteUI.Blazor": "23.2.223"

Steps to reproduce

1. Define a grid that has autoGenerate set to true.
2. Define a column in the markup.

<igc-grid auto-generate="true" id="grid">
    <igc-column field="ID"></igc-column>
</igc-grid>

private data: any[] = [
    { ID: 1, Product: "Chai", Category: "Beverages" },
    { ID: 2, Product: "Chang", Category: "Food" },
    { ID: 3, Product: "Tofu", Category: "Food" }
];

constructor() {
    const grid = document.getElementById("grid") as IgcGridComponent;
    grid.data = this.data;
}

Result

Only the defined ID column is rendered.

Expected result

The columns should be generated based on the provided data, i.e., three columns (ID, Product, Category) should be rendered.