Fix release from #1860 (hotfix #1934).

- Cron job to send weekly email report is processed multiple times. Review scheduling process to send to only one worker.
- Implement mechanism to ensure each email is sent only once to each recipient.
- Improve the way the async task is processed by creating a separate task for each organization, instead of processing all organizations in a single task.
ee/settings.py
"""
Django settings for PostHog Enterprise Edition.
"""
from posthog.settings import CLICKHOUSE, PRIMARY_DB, TEST
HOOK_EVENTS = {
    
    "action_defined": "posthog.Action.created_custom",
    "action_performed": "posthog.Action.performed",
    "annotation_created": "posthog.Annotation.created_custom",
}
HOOK_FINDER = "ee.models.hook.find_and_fire_hook"
HOOK_DELIVERER = "ee.models.hook.deliver_hook_wrapper"
KAFKA_ENABLED = PRIMARY_DB == CLICKHOUSE and not TEST