Outcommented the required attributes above certain fields in Address.cs

[Gobbenobber]

This outcomments required attributes above certain fields in Address.cs which otherwise results in an exception being thrown when following the guide from save-point 00, at save-point 02 (when clicking the order pizza button). See issue #339

[jongalloway]

All CLA requirements met.

[Gobbenobber]

I'll gladly just remove the required attribute itself for these three files, to avoid outcommented code. LMK if I need to change.

[danroth27]

This should be addressed now by https://github.com/dotnet-presentations/blazor-workshop/pull/354

[Gobbenobber]

Okay............. I will delete the branch then. Thanks for the swift reply though. 😃👍