Habits show positive/negative even if either of those are disabled

[imrehg]

Habits can have either positive or negative toggles disabled, and in the Habitica interface it shows with only the relevant button pressable.

Showing up as:

This plugin, however shows both options for every habit.

The correct behaviour should be likely to show ownly the relevant button and allowing only that to be pressed.

(I'm happy to send in a PR if that's preferred/acceptable, just have to dive in the code)