workflows: classifier results in workflow description fix

* Adds classifier results in holdingpen description column
  for proccess_record_arxiv workflow.


Actually the structure of `results.get('classification_*')` is:

```python
[{'name': 'classification_full',
 'result': {'dict': {'categories': {'4/3': 'HEP',
    '5/3': 'HEP',
    'Rb': 'HEP',
    'Riemann': 'HEP',
    'X/b': 'HEP',
    'Z(2)': 'HEP',
    'affine': 'HEP',
    'conformal': 'HEP',
    'dark matter': 'HEP',
    'e*': 'HEP',
    'electron': 'HEP',
    'positron': 'HEP',
    'transition radiation detector': 'HEP',
    'virial theorem': 'HEP'},
   'complete_output': {'Acronyms': {},
    'Author keywords': {},
    'Composite keywords': {'vector: Killing': {'details': [2, 2],
      'numbers': 1}},
    'Core keywords': {'X/b': 1, 'dark matter': 1},
    'Field codes': {},
    'Single keywords': {'4/3': 5,
     '5/3': 4,
     'Rb': 2,
     'Riemann': 1,
     'X/b': 1,
     'Z(2)': 3,
     'affine': 1,
     'conformal': 1,
     'dark matter': 1,
     'e*': 2,
     'electron': 1,
     'positron': 2,
     'transition radiation detector': 1,
     'virial theorem': 1}}},
  'fast_mode': False},
 'template': 'workflows/results/classifier.html'}]
```

Which means these lines should be:
```python
result_full[0].get('result').get('dict', {}).get('complete_output')
```
(Note the missing `.get('result')`)