message: fix: Dashboard API flaky test
diff: @@ -413,8 +413,8 @@ class TestDashboardApi(SupersetTestCase, ApiOwnersTestCaseMixin, InsertChartMixi
  from datetime import datetime
  import humanize
  + with freeze_time("2020-01-01T00:00:00Z"):
  admin = self.get_user("admin")
  - start_changed_on = datetime.now()
  dashboard = self.insert_dashboard("title", "slug1", [admin.id])
  self.login(username="admin")
  @@ -430,7 +430,7 @@ class TestDashboardApi(SupersetTestCase, ApiOwnersTestCaseMixin, InsertChartMixi
  data = json.loads(rv.data.decode("utf-8"))
  self.assertEqual(
  data["result"][0]["changed_on_delta_humanized"],
  - humanize.naturaltime(datetime.now() - start_changed_on),
  + humanize.naturaltime(datetime.now()),
  )
  # rollback changes
  