### 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)

""":return: whether all file paths have been processed max_runs times"""
        if self._max_runs == -1:  
            return False
        for stat in self._file_stats.values():
            if stat.run_count < self._max_runs:
                return False
        if self._num_run < self._max_runs:
            return False
        return True
    def terminate(self):
        """
        Stops all running processors
        :return: None
        """
        for processor in self._processors.values():
            Stats.decr("dag_processing.processes")
            processor.terminate()
    def end(self):