Check if conn.commit() is required

We have several methods that load data into the database from the JSON files. Because we have been using SQLite a lot, we typically don't encounter issues. However, other databases may explicitly require us to use `conn.commit()` or similar to commit things like inserts or updates to the database. This is a newer requirement of SQLAlchemy 2.0. I think this is an un-caught bug in our codebase.

We should run some tests with a Postgres database to see if this is indeed the case and add them as part of the underlying methods.