Part of https://github.com/twentyhq/core-team-issues/issues/526
An active workspace's defaultRoleId should never be null.
We can't rely on a simple postgres NOT NULL constraint as defaultRoleId
will always be initially null when the workspace is first created since
the roles do not exist at that time.
Since a suspended workspace can be active again, we should maintain that
rule during the workspace suspension. The only moment defaultRoleId can
have a null value is during the onboarding. this pr enforces that