Add support for negated weight filtering

What does this MR do?

Adds support issue for negated weight filtering on the backend. #223201 (closed)

Database Details

Issueable Finder Query

SELECT "issues".*
FROM "issues"
INNER JOIN "projects" ON "projects"."id" = "issues"."project_id"
LEFT JOIN project_features ON projects.id = project_features.project_id
WHERE "projects"."namespace_id" IN
    (WITH RECURSIVE "base_and_descendants" AS (
                                                 (SELECT "namespaces".*
                                                  FROM "namespaces"
                                                  WHERE "namespaces"."type" = 'Group'
                                                    AND "namespaces"."id" = 9970)
                                               UNION
                                                 (SELECT "namespaces".*
                                                  FROM "namespaces",
                                                       "base_and_descendants"
                                                  WHERE "namespaces"."type" = 'Group'
                                                    AND "namespaces"."parent_id" = "base_and_descendants"."id")) SELECT "namespaces"."id"
     FROM "base_and_descendants" AS "namespaces")
  AND (EXISTS
         (SELECT 1
          FROM "project_authorizations"
          WHERE "project_authorizations"."user_id" = 4156052
            AND (project_authorizations.project_id = projects.id))
       OR projects.visibility_level IN (0,
                                        10,
                                        20))
  AND ("project_features"."issues_access_level" > 0
       OR "project_features"."issues_access_level" IS NULL)
  AND ("issues"."state_id" IN (1))
  AND "projects"."archived" = false
  AND "issues"."issue_type" IN (0,
                                1)
  AND ("issues"."weight" IS NULL
       OR "issues"."weight" != 4)
  AND "projects"."archived" = false
ORDER BY "issues"."created_at" DESC,
         "issues"."id" DESC
LIMIT 20
OFFSET 0

https://explain.depesz.com/s/vMQu

Screenshots (strongly suggested)

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team