[HGrid] Update code snippet in Row editing actions topic

1. Open [Custom Implementation](https://staging.infragistics.com/products/ignite-ui-blazor/blazor/components/grids/hierarchical-grid/row-actions#custom-implementation) section 
2. Snippet differs from actual code:

<img width="842" height="776" alt="Image" src="https://github.com/user-attachments/assets/670d1e5b-3321-469e-a41e-57be4a91905a" />