Even if a PopIt ID was blacklisted, a speech might still end up
being associated with that person because there would still be a
Speaker object with the exact name that's being resolved which
has its person attribute set to a Person with the blacklisted
PopIt ID.
This commit makes sure that any Speaker with a person attribute
with a blacklisted PopIt ID has that person attribute set to None
when the ImportJson object is initialized.
Even if a PopIt ID was blacklisted, a speech might still end up being associated with that person because there would still be a Speaker object with the exact name that's being resolved which has its person attribute set to a Person with the blacklisted PopIt ID.
This commit makes sure that any Speaker with a person attribute with a blacklisted PopIt ID has that person attribute set to None when the ImportJson object is initialized.
Fixes #1740