Fix not_in search with deep nesting

[giovannelli]

Description

This pull request addresses issue #1411, where the generated SQL query for excluding articles based on associated tags was incorrect (I've used tags the my example).

The current query joins and filters tags improperly, resulting in an unintended query structure. Specifically, the subquery logic used for filtering tags produces incorrect results and may impact performance.

SELECT "articles".* 
FROM "articles" 
LEFT OUTER JOIN "comments" 
  ON "comments"."disabled" = 0 
  AND "comments"."article_id" = "articles"."id" 
WHERE ('default_scope' = 'default_scope') 
  AND "articles"."id" NOT IN (
    SELECT "comments_tags"."comment_id" 
    FROM "comments_tags" 
    INNER JOIN "tags" 
      ON "tags"."id" = "comments_tags"."tag_id" 
    WHERE "comments_tags"."comment_id" = "articles"."id" 
      AND NOT ("tags"."name" NOT IN ('Fantasy', 'Scifi'))
  )

The solution modifies the query structure to use proper joins and filtering, simplifying the SQL and ensuring correct results.

SELECT "articles".* 
FROM "articles" 
LEFT OUTER JOIN "comments" 
  ON "comments"."disabled" = 0 
  AND "comments"."article_id" = "articles"."id" 
LEFT OUTER JOIN "comments_tags" 
  ON "comments_tags"."comment_id" = "comments"."id" 
LEFT OUTER JOIN "tags" 
  ON "tags"."id" = "comments_tags"."tag_id" 
WHERE ('default_scope' = 'default_scope') 
  AND "tags"."name" NOT IN ('Fantasy', 'Scifi')