### 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)

os.environ["CONFIG_PROCESSOR_MANAGER_LOGGER"] = "True"
        os.environ["AIRFLOW__LOGGING__COLORED_CONSOLE_LOG"] = "False"
        
        
        
        
        
        
        
        
        
        
        importlib.reload(import_module(airflow.settings.LOGGING_CLASS_PATH.rsplit(".", 1)[0]))  
        importlib.reload(airflow.settings)
        airflow.settings.initialize()
        del os.environ["CONFIG_PROCESSOR_MANAGER_LOGGER"]
        processor_manager = DagFileProcessorManager(
            dag_directory=dag_directory,
            max_runs=max_runs,
            processor_timeout=processor_timeout,
            dag_ids=dag_ids,
            pickle_dags=pickle_dags,
            signal_conn=signal_conn,
            async_mode=async_mode,
        )
        processor_manager.start()
    def heartbeat(self) -> None: