This commit changes the `StatusChatInput` component to also be a `StatusUpdateInput`.
The latter isn't an actual new type or component, it's just a visual variation of the already
existing status chat input. That's my most of the changes are `isStatusUpdateInput` conditions
sprinkled here and there.
In addition, this commit introduces a new `chatType` which is passed to `StatusChatInput` later
in the timeline view, so it knows it has to render like a status update input.