Until now, when writing `create(:poll_answer, option: option)`, the
`answer` field would take the title of a random option instead of taking
the title from the `option` variable.
So now, if we're given the option, the `answer` field will be taken from
the option itself.
Note that writing something like:
```
option { question.question_options.find_by(title: answer) }
answer { option.title }
```
Would create an infinite loop when creating a poll answer if we don't
pass the `option` and/or the `answer` attributes.
So, instead, we're making the `option` depend on the `answer` attribute
exclusively when we pass the `answer` attribute to the factory.
fd14c55615