Context:
When querying dag runs in the stable API, it is possible to filter by date range and to receive paginated results. Pagination returns a subset of results, but a count of all available results is returned.

Expected behavior:
The total count should take place after filtering by date, and before paginating results.

Actual behavior:
The count is made prior to filtering by date. This means that the total number of accessible dags is returned, rather than the number of dags the user filtered for.

https://github.com/apache/airflow/pull/10594/files/1fe1da978763c9919cee0d2c7eccd96438631993#diff-3239f89a092764597348cabc5e74c2f5R125

I will make this change after #10594 is merged.
tests/api_connexion/endpoints/test_dag_run_endpoint.py
"api/v1/dags/TEST_DAG_ID/dagRuns?execution_date_lte=2020-06-13T18:00:00+00:00",
                [
                    "TEST_START_EXEC_DAY_10",
                    "TEST_START_EXEC_DAY_11",
                    "TEST_START_EXEC_DAY_12",
                    "TEST_START_EXEC_DAY_13",
                ],
            ),
            (
                "api/v1/dags/TEST_DAG_ID/dagRuns?execution_date_gte=2020-06-16T18:00:00+00:00",
                [
                    "TEST_START_EXEC_DAY_16",
                    "TEST_START_EXEC_DAY_17",
                    "TEST_START_EXEC_DAY_18",
                    "TEST_START_EXEC_DAY_19",
                ],
            ),
        ]
    )
    @provide_session
    def test_date_filters_gte_and_lte(self, url, expected_dag_run_ids, session):
        dagrun_models = self._create_dag_runs()
        session.add_all(dagrun_models)
        session.commit()
        response = self.client.get(url, environ_overrides={'REMOTE_USER': "test"})
        assert response.status_code == 200
        assert response.json["total_entries"] == 10
        dag_run_ids = [dag_run["dag_run_id"] for dag_run in response.json["dag_runs"]]
        assert dag_run_ids == expected_dag_run_ids
    def _create_dag_runs(self):