fix(tests): Fix flaky test_snuba_data timestamp precision mismatch

Strip microseconds from the test event timestamp since Snuba truncates
timestamps to second precision. This caused intermittent assertion
failures when comparing nodestore vs Snuba timestamp values.

Fixes #109056

Author: joshuarli

tests/sentry/services/eventstore/test_models.py

@@ -212,7 +212,7 @@ def test_snuba_data(self) -> None:
                 "message": "Hello World!",
                 "tags": {"logger": "foobar", "site": "foo", "server_name": "bar"},
                 "user": {"id": "test", "email": "test@test.com"},
-                "timestamp": before_now(seconds=1).isoformat(),
+                "timestamp": before_now(seconds=1).replace(microsecond=0).isoformat(),
             },
             project_id=self.project.id,
         )