In commit 9329e4b6e, `try` was added because there was a case where this
partial was rendered and the `current_booth` method didn't exist.
However, that's no longer the case since commit d5c7858f6. Since then,
this partial is only rendered in the officing section, where the
`current_booth` method is defined.
So we can use the safe navigation operator instead of `try`.
a15ff36a22