Excel style filtering for strings throws errors in the console

[ilijev07]

Description

Excel style filtering for strings throws errors in the console when there are value in the grid which have just one letter or number.

Its introduced from this changes -> #14906

• igniteui-angular version: 17.2.25
• browser: Chrome Version 131.0.6778.86

Steps to reproduce

Here is Stackblitz link -> https://stackblitz.com/edit/e7anky?file=src%2Fapp%2Fdata%2FnwindData.ts,src%2Fapp%2Fdirectives%2Fprevent-scroll.directive.ts

1. Have data in the grid with string type of column and enter data values with just 1 letter or 1 number
2. Try filtering withTextFilter and filter with any of (startsWith, endsWith, equals, does not equal)
3. Enter the letter or the number and press Apply (for example in the Product Names column, there are such entries: "2", "3" and "s" use any of those and observe the console)

Result

Even though the filtering works it throws error in the console

Expected result

No errors in the console

Note

I explored the codebase, the issue is in excel-style-filtering.component.ts in the renderValues and modifyExpression methods

 private renderValues() {
        this.filterValues = this.generateFilterValues();
        this.generateListData();
        this.expressionsList.forEach(expr => {
            if (this.column.dataType === GridColumnDataType.String && this.column.filteringIgnoreCase && expr.expression.searchVal) {
                this.modifyExpression(expr);
            }
        });
    }
    
     private modifyExpression(expr: ExpressionUI) {
        const lowerCaseFilterValues = new Set(Array.from(expr.expression.searchVal).map((value: string) => value.toLowerCase()));

        this.grid.data.forEach(item => {
            if (lowerCaseFilterValues.has(item[this.column.field]?.toLowerCase())) {
                expr.expression.searchVal.add(item[this.column.field]);
            }
        });
    }

the modifyExpression method tries to add in searchVal a value, but a searchVal is a string. I assume the if statement of renderValues should cover this scenario.