- Implements `skip` choice, which acts as a placeholder in the player
choices. This is relevant to double-KOs, since in-game you are allowed
to specify switch-ins in any order.
Among the added tests, are included:
- A skipped test for an edge case in which usage of Reflect Type
causes a typing information leak via the presence/absence of the
"maybe-trapped" warning and cancel prevention.
- Two skipped tests related to partial decisions functionality.
- Basically, support is added only for `move` requests here, and
behind a flag (`battle.supportsPartialDecision`).
- Switching is mostly supported, except for the multiple-KOs case.
- Team Preview needs a rework in order to enable this feature.
