Edge case with non paired read with no primers

### Description of the bug

```
  File "/home/chris/chris-data/lib/python3.10/site-packages/align_trim/main.py", line 375, in handle_segments
    segment = segment1 if segment1 else segment2
UnboundLocalError: local variable 'segment1' referenced before assignment
```

### Command used and terminal output

```console

```

### Relevant files

_No response_

### System information

_No response_