temporary_label_id stored as Option[Int] in Database

[michaelduan8]

As described in the title, temporary_label_ids (which are used to locate labelId in the database upon form submission, for example) are stored as Option[Int], which seems strange considering how it is needed to identify if a label already exists in the database

[misaugstad]

I checked all the databases, and it seems that the temporary_label_id is not null for any label except in the DC database. But the DC database is using the old code base anyway. So we may as well switch this to appropriately require non-null temporary label IDs.