Issue #3585521: NotificationRequiredCondition should filter purge_users_notifications on type = 'notification_users'

Closes #3585521.

Summary

NotificationRequiredCondition (labeled Users pre-notified only) was doing an INNER JOIN on purge_users_notifications without filtering on the type column, so any row satisfied the condition — including type = 'purge_users' rows written by UserManagementService::notifyUserToPurge() at deletion time. A 'purge_users' row is not a pre-notification, so it must not make a user purgeable under this condition.

Change

• src/Plugin/Condition/NotificationRequiredCondition.php: add AND pun.type = :type (with 'notification_users') to the inner join predicate.

Tests

tests/src/Kernel/policy/NotificationRequiredTypeFilterTest.php exercises the four row combinations plus a recency edge case:

• 'notification_users' row older than the delay → purgeable.
• Only 'purge_users' row → NOT purgeable.
• Both rows present (older than delay) → purgeable.
• Recent 'notification_users' row (younger than delay) → NOT purgeable.
• No rows → NOT purgeable.

All 5 pass; full kernel suite (109 tests) green.

Related

• #3521201 — global path PurgeUsersHelper::checkNotification() already filters type = 'notification_users'.
• #3585503 / !54 — configurable handling of users with empty or malformed email addresses (same area of the codebase).