Chapter 03 --> BlazorHolData ---> Add New Person causes an exception if Data.Database.People is emptied first

[jhogan05]

Possible solution is to check first. There are other solutions on StackOverflow for this issue
(e.g https://stackoverflow.com/questions/6966680/max-return-value-if-empty-query)

   else
    {
        int newtId = Data.Database.People.Any() ?  Data.Database.People.Max(p => p.Id) + 1 : 1;
        Person!.Id = newtId;
        Data.Database.People.Add(Person);
    }