[Bug] batch processing bug : wrong output directory names with spleeter 2.3.2

- [X] I didn't find a similar issue already open.
- [X] I read the documentation (README AND Wiki)
- [X] I have installed FFMpeg
- [X] My problem is related to Spleeter only, not a derivative product (such as Webapplication, or GUI provided by others)

## Description

When using spleeter program for processing a batch of file, the first file of the batch is processed twice : in the first and in the second output produced by spleeter.
Remaining output names are mismatched : output N correspond to input N-1
Last input file is not associated to any output.

## Step to reproduce

1. Installed using `pip install spleeter`
2. Run as `spleeter separate -p spleeter:2stems -o spleeter_output 1.wav 2.wav 3.wav`

Input files have same encoding, but distinct durations to help showing the bug : 1.wav is 1 Mb, 2.wav is 2 Mb and 3.wav is 4 Mb
```bash
ddoukhan@rex-gpu10:~$ file *.wav
1.wav: RIFF (little-endian) data, WAVE audio, Microsoft PCM, 16 bit, stereo 44100 Hz
2.wav: RIFF (little-endian) data, WAVE audio, Microsoft PCM, 16 bit, stereo 44100 Hz
3.wav: RIFF (little-endian) data, WAVE audio, Microsoft PCM, 16 bit, stereo 44100 Hz

ddoukhan@rex-gpu10:~$ ls -lah *.wav
-rw-rw-r-- 1 ddoukhan ddoukhan 1,1M déc. 6 12:47 1.wav
-rw-rw-r-- 1 ddoukhan ddoukhan 2,1M déc. 6 12:47 2.wav
-rw-rw-r-- 1 ddoukhan ddoukhan 4,1M déc. 6 12:47 3.wav
```

## Output

I would expect :
* files in folder spleeter_output/1 to be of size 1 Mb (True).
* files in folder spleeter_output/2 to be of size 2 Mb (False)
* files in folder spleeter_output/3 to be of size 4 Mb (False)

```bash
ddoukhan@rex-gpu10:~$ ls -lah spleeter_output/*/*.wav
-rw-rw-r-- 1 ddoukhan ddoukhan 1,1M déc. 6 12:49 spleeter_output/1/accompaniment.wav
-rw-rw-r-- 1 ddoukhan ddoukhan 1,1M déc. 6 12:49 spleeter_output/1/vocals.wav
-rw-rw-r-- 1 ddoukhan ddoukhan 1,1M déc. 6 12:49 spleeter_output/2/accompaniment.wav
-rw-rw-r-- 1 ddoukhan ddoukhan 1,1M déc. 6 12:49 spleeter_output/2/vocals.wav
-rw-rw-r-- 1 ddoukhan ddoukhan 2,1M déc. 6 12:49 spleeter_output/3/accompaniment.wav
-rw-rw-r-- 1 ddoukhan ddoukhan 2,1M déc. 6 12:49 spleeter_output/3/vocals.wav
```
Output files have same encoding than input file (expected)
```bash
ddoukhan@rex-gpu10:~$ file spleeter_output/*/*
spleeter_output/1/accompaniment.wav: RIFF (little-endian) data, WAVE audio, Microsoft PCM, 16 bit, stereo 44100 Hz
spleeter_output/1/vocals.wav: RIFF (little-endian) data, WAVE audio, Microsoft PCM, 16 bit, stereo 44100 Hz
spleeter_output/2/accompaniment.wav: RIFF (little-endian) data, WAVE audio, Microsoft PCM, 16 bit, stereo 44100 Hz
spleeter_output/2/vocals.wav: RIFF (little-endian) data, WAVE audio, Microsoft PCM, 16 bit, stereo 44100 Hz
spleeter_output/3/accompaniment.wav: RIFF (little-endian) data, WAVE audio, Microsoft PCM, 16 bit, stereo 44100 Hz
spleeter_output/3/vocals.wav: RIFF (little-endian) data, WAVE audio, Microsoft PCM, 16 bit, stereo 44100 Hz

```

## Environment

| | |
| ----------------- | ------------------------------- |
| OS | Ubuntu 22.04 & Ubuntu 20.04 |
| Installation type | pip |
| spleeter version | 2.3.2 |
| RAM available | 64 Go |
| Hardware spec | GPU Nvidia 1080 TI |

## Additional context