[BUG] failed to solve: rm /opt/conda/bin/ffmpeg && ln -s /bin/ffmpeg /opt/conda/bin/ffmpeg

When I use `docker compose build` I encounter the following problem：

```plaintext
------
> [backend 7/15] RUN rm /opt/conda/bin/ffmpeg && ln -s /bin/ffmpeg /opt/conda/bin/ffmpeg:
0.117 rm: cannot remove '/opt/conda/bin/ffmpeg': No such file or directory
------
failed to solve: process "/bin/sh -c rm /opt/conda/bin/ffmpeg && ln -s /bin/ffmpeg /opt/conda/bin/ffmpeg" did not complete successfully: exit code: 1
```

I found that changing
```dockerfile
RUN rm /opt/conda/bin/ffmpeg && ln -s /bin/ffmpeg /opt/conda/bin/ffmpeg
```
to
```dockerfile
RUN [ -f /opt/conda/bin/ffmpeg ] && rm /opt/conda/bin/ffmpeg; ln -s /bin/ffmpeg /opt/conda/bin/ffmpeg
```
resolves the issue.