Refactors how KVO is setup. Removes observers for `position` from `self.layer`, causing a crash in `SLKTextInputbar`.
Refactors how KVO is setup. Removes observers for `position` from `self.layer`, causing a crash in `SLKTextInputbar`.

slackhq/SlackTextViewController,kobim/SlackTextViewController,slackhq/SlackTextViewController,kobim/SlackTextViewController