Sentry Issue: [POSTHOG-37H](https://sentry.io/organizations/posthog/issues/2511149053/?referrer=github_integration)

```
AttributeError: 'NoneType' object has no attribute 'strftime'
(3 additional frame(s) were not displayed)
...
  File "ee/clickhouse/views/insights.py", line 90, in calculate_funnel
    "result": ClickhouseFunnelTrends(team=team, filter=filter, funnel_order_class=funnel_order_class).run()
  File "ee/clickhouse/queries/funnels/base.py", line 48, in run
    results = self._exec_query()
  File "ee/clickhouse/queries/funnels/funnel_trends.py", line 61, in _exec_query
    return self._summarize_data(super()._exec_query())
  File "ee/clickhouse/queries/funnels/base.py", line 118, in _exec_query
    query = self.get_query()
  File "ee/clickhouse/queries/funnels/funnel_trends.py", line 112, in get_query
    {interval_method}(toDateTime('{self._filter.date_from.strftime(TIMESTAMP_FORMAT)}') + number * {seconds_in_interval}) AS entrance_period_start
```
ee/clickhouse/queries/funnels/funnel_trends.py
self, filter: Filter, team: Team, funnel_order_class: Type[ClickhouseFunnelBase] = ClickhouseFunnel
    ) -> None:
        super().__init__(filter, team)
        self.funnel_order = funnel_order_class(filter, team)
    def _exec_query(self):
        return self._summarize_data(super()._exec_query())
    def get_step_counts_without_aggregation_query(
        self, *, specific_entrance_period_start: Optional[datetime] = None
    ) -> str:
        steps_per_person_query = self.funnel_order.get_step_counts_without_aggregation_query()
        interval_method = get_trunc_func_ch(self._filter.interval)
        # Th
        if specific_entrance_period_start:
            self.params["entrance_period_start"] = specific_entrance_period_start.strftime(TIMESTAMP_FORMAT)
        breakdown_clause = self._get_breakdown_prop()
        return f"""
            SELECT
                person_id,
                {interval_method}(timestamp) AS entrance_period_start,
                max(steps) AS steps_completed
                {breakdown_clause}
            FROM (
                {steps_per_person_query}
            )
            {"WHERE toDateTime(entrance_period_start) = %(entrance_period_start)s" if specific_entrance_period_start else ""}
            GROUP BY person_id, entrance_period_start {breakdown_clause}"""
    def get_query(self) -> str: