### Apache Airflow version

2.4.1

### What happened

When there are large number of dag files, lets say 10K and each takes sometime to parse,  dag_parser doesnt pick any newly created files till all 10k files are finished parsing

`if not self._file_path_queue:
                self.emit_metrics()
                self.prepare_file_path_queue()`

Above logic only adds new files to queue when queue is empty

### What you think should happen instead

Every loop of dag processor should pick new files and add into file for parsing queue

### How to reproduce

_No response_

### Operating System

All

### Versions of Apache Airflow Providers

_No response_

### Deployment

Docker-Compose

### Deployment details

_No response_

### Anything else

_No response_

### Are you willing to submit PR?

- [X] Yes I am willing to submit a PR!

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)

with create_session() as session:
            
            dag = dagbag.get_dag("test_example_bash_operator")
            dag.last_parsed_time = timezone.utcnow()
            dag.sync_to_db(processor_subdir=dag_directory)
            
            other_dag = other_dagbag.get_dag("test_start_date_scheduling")
            other_dag.last_parsed_time = timezone.utcnow()
            other_dag.sync_to_db(processor_subdir="other")
            
            stat = DagFileStat(
                num_dags=1,
                import_errors=0,
                last_finish_time=timezone.utcnow() + timedelta(hours=1),
                last_duration=1,
                run_count=1,
            )
            manager._file_paths = [test_dag_path]
            manager._file_stats[test_dag_path] = stat
            active_dag_count = session.query(func.count(DagModel.dag_id)).filter(DagModel.is_active).scalar()
            assert active_dag_count == 2
            manager._deactivate_stale_dags()
            active_dag_count = session.query(func.count(DagModel.dag_id)).filter(DagModel.is_active).scalar()
            assert active_dag_count == 1
    @mock.patch(
        "airflow.dag_processing.processor.DagFileProcessorProcess.waitable_handle", new_callable=PropertyMock
    )
    @mock.patch("airflow.dag_processing.processor.DagFileProcessorProcess.pid", new_callable=PropertyMock)
    @mock.patch("airflow.dag_processing.processor.DagFileProcessorProcess.kill")
    def test_kill_timed_out_processors_kill(self, mock_kill, mock_pid, mock_waitable_handle):