TextSeparator = ", " for concatenating errors

[michaelcsikos]

The standard validation error messages such as [Required] are proper sentences ending with a . and I think this is good practice. Csla.Blazor.PropertyInfo assumes error messages won't end with a . using ", " to concatenate errors, so you end up with:

Should TextSeparator = " " or perhaps be a public static string TextSeparator { get; set; } instead?

[rockfordlhotka]

It seems like something someone could set, and perhaps the default should be " ".