Don't force actionbar buttons on small screen

Layouts should generally use `ifRoom` instead of `always` for actionbar buttons in case the user has a device with a small screen. They will also show/hide properly when you rotate your device this way.

I don't think this was actually causing problems in Conversations (as it was just one or two icons), but just in case we might as well follow best practices. It shouldn't cause any issues on screens that are large enough to display all the icons (a few people might find that the lowest priority one is hidden now and they have a bit more room between the buttons and the title/home button).