ref(daily summary): Fix timezone (#66563)

Using `floor_to_utc_day` made the timestamp always UTC midnight which
equates to PST 4pm - this wasn't caught in tests because the timestamp
was being passed in so this code path wasn't being hit. This should
prevent the resending each hour to only sending at 4pm at the user's
local time as intended.

src/sentry/tasks/summaries/daily_summary.py

@@ -41,7 +41,7 @@
 from sentry.types.activity import ActivityType
 from sentry.types.group import GroupSubStatus
 from sentry.types.integrations import ExternalProviders
-from sentry.utils.dates import floor_to_utc_day, to_datetime, to_timestamp
+from sentry.utils.dates import to_datetime, to_timestamp
 from sentry.utils.outcomes import Outcome
 from sentry.utils.query import RangeQuerySetWrapper
 
@@ -62,7 +62,7 @@
 def schedule_organizations(timestamp: float | None = None, duration: int | None = None) -> None:
     if timestamp is None:
         # The time that the report was generated
-        timestamp = to_timestamp(floor_to_utc_day(timezone.now()))
+        timestamp = to_timestamp(timezone.now())
 
     if duration is None:
         # The total timespan that the task covers

tests/sentry/tasks/test_daily_summary.py

@@ -203,6 +203,23 @@ def test_schedule_organizations(self, mock_prepare_summary_data):
                 [self.user.id],
             )
 
+    @with_feature("organizations:daily-summary")
+    @mock.patch("sentry.tasks.summaries.daily_summary.prepare_summary_data")
+    def test_schedule_organizations_timing(self, mock_prepare_summary_data):
+        with self.tasks(), freeze_time("2024-03-06 23:15:00"):  # 3:15PM PST
+            schedule_organizations()
+        assert mock_prepare_summary_data.delay.call_count == 0
+
+        with self.tasks(), freeze_time("2024-03-07 00:00:00"):  # 4PM PST
+            schedule_organizations()
+        assert mock_prepare_summary_data.delay.call_count == 1
+
+        with self.tasks(), freeze_time("2024-03-07 01:00:00"):  # 5PM PST
+            schedule_organizations()
+        assert (
+            mock_prepare_summary_data.delay.call_count == 1
+        )  # note this didn't fire again, it just didn't increase from before
+
     def test_build_summary_data(self):
         self.populate_event_data()
         summary = build_summary_data(