### 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)

child_pipe, parent_pipe = multiprocessing.Pipe()
        with TemporaryDirectory(prefix="empty-airflow-dags-") as dags_folder:
            async_mode = "sqlite" not in conf.get("database", "sql_alchemy_conn")
            manager = DagFileProcessorManager(
                dag_directory=dags_folder,
                max_runs=1,
                processor_timeout=timedelta(days=365),
                signal_conn=child_pipe,
                dag_ids=[],
                pickle_dags=False,
                async_mode=async_mode,
            )
            self.run_processor_manager_one_loop(manager, parent_pipe)
        child_pipe.close()
        parent_pipe.close()
    @pytest.mark.backend("mysql", "postgres")
    def test_start_new_processes_with_same_filepath(self):