Four new columns were added to the `wh_user_dimension` table to support
OIDC. The data type for the columns was originally `wh_dim_text` which
is a domain type with a `not null` restriction. Adding the new columns
caused the migration to fail if the `wh_user_dimension` table had any
rows in it because the existing rows would violate the `not null`
restriction.
Closes#1469