## Bug description

When using the overall date filter on dashboards, after refreshing the dashboarditem will still show old data

## Expected behavior

Should show data that matches the overall filter

## How to reproduce

1. Add item to dashboard
2. Filter entire dashboard on date
3. refresh date

## Environment

- [ ] PostHog Cloud
- [ ] self-hosted PostHog, version/commit: _please provide_

## Additional context



#### *Thank you* for your bug report – we love squashing them!

posthog/models/dashboard_item.py
if dashboard is None:
            dashboard = self.dashboard
        if dashboard:
            return {**self.filters, **dashboard.filters}
        else:
            return self.filters
@receiver(pre_save, sender=Dashboard)
def dashboard_saved(sender, instance: Dashboard, **kwargs):
    for item in instance.items.all():
        dashboard_item_saved(sender, item, dashboard=instance, **kwargs)
@receiver(pre_save, sender=DashboardItem)
def dashboard_item_saved(sender, instance: DashboardItem, dashboard=None, **kwargs):
    if instance.filters and instance.filters != {}:
        filter = get_filter(data=instance.dashboard_filters(dashboard=dashboard), team=instance.team)
        instance.filters = filter.to_dict()
        instance.filters_hash = generate_cache_key("{}_{}".format(filter.toJSON(), instance.team_id))