🐛 Fixed "Send" publish type not being reset when closing publish menu
🐛 Fixed "Send" publish type not being reset when closing publish menu

refs https://github.com/TryGhost/Team/issues/1151

- we were setting `emailOnly` on the publish menu component but not resetting it meaning when you re-opened the menu after previously selecting "Send" the menu would still show "Send" but the state was inconsistent because the underlying `distributionAction` property _was_ reset
- dropped setting `emailOnly` directly in favour of making it a computed property based on `distributionAction === 'send'` so we only have to worry about changing distribution action and everything else updates for us automatically

TryGhost/Ghost,TryGhost/Ghost,TryGhost/Ghost