Add LangPro predicted entailment label

The user currently has to inspect the LangPro-generated tableaus to see what LangPro's judgement of a problem is (contradiction, entailment, neutral or conflict). It would help if this could be displayed somewhere on the page. It should not overwrite the existing entailment label that is part of the dataset.

The entailment label can be inferred from the tableau output:

| Entailment tree closed| Contradiction tree closed| Resulting judgement |
|--------|--------|--------|
| ✖️ | ✔️ | Contradiction |
| ✔️ | ✖️ | Entailment |
| ✔️ | ✔️ | Conflict|
| ✖️ | ✖️ | Neutral |

This predicted entailment label should only be saved to the DB once 'Save problem' is pressed.