## Is your feature request related to a problem?

I want to run experiments on groups

## Describe the solution you'd like

Experiments support group target metrics, and the FF respects group selection.


## Describe alternatives you've considered

No groups :(

## Additional context



#### *Thank you* for your feature request – we love each and every one!

ee/clickhouse/views/test/test_clickhouse_experiments.py
self.assertEqual(response.json()["name"], "Test Experiment")
        self.assertEqual(response.json()["feature_flag_key"], ff_key)
        created_ff = FeatureFlag.objects.get(key=ff_key)
        self.assertEqual(created_ff.key, ff_key)
        self.assertEqual(created_ff.active, True)
        self.assertEqual(created_ff.filters["multivariate"]["variants"][0]["key"], "control")
        self.assertEqual(created_ff.filters["multivariate"]["variants"][1]["key"], "test_1")
        self.assertEqual(created_ff.filters["multivariate"]["variants"][2]["key"], "test_2")
        self.assertEqual(created_ff.filters["groups"][0]["properties"][0]["key"], "$geoip_country_name")
        id = response.json()["id"]
        
        response = self.client.patch(
            f"/api/projects/{self.team.id}/experiments/{id}",
            {
                "description": "Bazinga",
                "parameters": {"feature_flag_variants": [{"key": "control", "name": "X", "rollout_percentage": 33}]},
            },
        )
        self.assertEqual(response.status_code, status.HTTP_400_BAD_REQUEST)
        self.assertEqual(response.json()["detail"], "Can't update feature_flag_variants on Experiment")
        
        response = self.client.patch(
            f"/api/projects/{self.team.id}/experiments/{id}",
            {
                "description": "Bazinga",
                "parameters": {
                    "feature_flag_variants": [
                        {"key": "control", "name": "Control Group", "rollout_percentage": 34},
                        {"key": "test_1", "name": "Test Variant", "rollout_percentage": 33},
                        {"key": "test_2", "name": "Test Variant", "rollout_percentage": 32},