Adds a not condition to the query.
The not() function adds a not condition to a PublicPlansQueryBuilder. A query with a not
returns all the items that match the query as defined up to the not
function, but don't match the query passed to the not function.
If the query only contains a not() function, it returns all the items
that don't match the query defined by the not method.
A query to add to the initial query as a not condition.