Numeric types have improper scale

In Postgres/CockroachDB if a column is defined with just precision and no scale, the scale is assumed to be 0 (ex. `NUMERIC(10)` -> `NUMERIC(10,0)`), but ActiveRecord treats this as a NUMERIC without scale defined, which means it can have digits to the right of the decimal place.

We are going to match the ActiveRecord behavior, but use this to track it and check if the behavior changes eventually.