Enforce returned records having all column properties exist even if empty

[annieyro]

A quirk of the Airtable API is that when it returns records, it will only populate fields if they are non-empty, which is pretty annoying.

Ex: Trying to get products by productIds from a store; initializing productIds to an empty array in the fromAirtableFormat might be useful.

This quirk has caused a few small bugs so think it might be worth pre-filling all the fields (since we know what they are from the schema) to be the correct empty type ('', {}, etc).