[react-mui-hooks] useDataGrid onPage function return type

[DorijanH]

Current behaviour

The onPage return type

{
    rows: GridValidRowModel[];
    totalRowsCount?: number
}

is not defined as a type and available to be reused outside the hook.

Expected behaviour

It would be nice to not have to explicitly know the type declaration and be able to reuse it when defining handlers for the onPage property.