At least one row should be there in GRN Item grid if it is the one line item in that grid we do not allow to delete it if we have more than 1 item allow to delete in power pages
Single Line Item:
If there is only one item in the grid, we prevent deletion of that item. It ensures that there is always at least one row present.
Multiple Items:
When there are multiple items, we allow deletion of any item from the grid.