PhoneNumber supports empty string?

[JonathanAsbury-Dovaxis]

Is your feature request related to a problem? Please describe.

PhoneNumber is null. But some NoSQL databases do not allow inserting Null Properties, like Firestore. Consequently, all null PhoneNumbers need to be deleted from the object array prior to inserting, or a process needs to set nulls to "" and then convert them back to null.

Describe the solution you'd like
Curious is a flag could be set on how to handle empty strings to account for this. More specifically, if allowEmptyStrings = true, then
serializing/deserializing wouldn't fail? Alternatively, a empty space regex could be used instead.

Describe alternatives you've considered
Using my own parser, which is what I'm going to do.

Additional context
I realize this issue is uniquely tied to Firebase, but sharing is caring, right? Planning to switch to MongoDb which allows null properties.