Add with_enrichment_filters scope to Security Policy

What does this MR do and why?

As proposed in #585514, we are adding a cron job to refresh MR approvals for updated package metadata automatically. One of the required steps is to retrieve all policies with enrichment filters for a given project.

This MR adds a new scope with_enrichment_filters to the Security::Policy model.

This draft MR illustrates how the new scope is intended to be used.

New query

SELECT DISTINCT
	"security_policies".*
FROM
	"security_policies"
	INNER JOIN "security_policy_project_links" ON "security_policies"."id" = "security_policy_project_links"."security_policy_id"
	INNER JOIN "approval_policy_rules" ON "approval_policy_rules"."security_policy_id" = "security_policies"."id"
WHERE
	"security_policy_project_links"."project_id" = 78097844
	AND (rule_index >= 0)
	AND (approval_policy_rules.content -> 'vulnerability_attributes' ->> 'known_exploited' IS NOT NULL
		OR approval_policy_rules.content -> 'vulnerability_attributes' -> 'epss_score' IS NOT NULL)
	AND "security_policies"."enabled" = TRUE

https://console.postgres.ai/gitlab/gitlab-production-main/sessions/48156/commands/144960

References

Related to: #585514

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