Update does not update if required fields are not set

[jewzaam]

Tried updating a document today and it didn't fail. Match count is 0 but updated count is 1. No error in the response. Went to logs and saw an ERROR for my update request saying a required field was not set. Two issues.

1. this shouldn't stop the update probably
2. if it does stop the update, it should propagate up to the caller!

[paterczm]

3. Introduce a concept of a default value. Can use existing value generator api to handle it. That's in addition to sending an error to the caller if there is no default and required value was not provided.