We split out a separate state for 'missed' separate to 'ended' which
caused confusion as the state got set to this when it shouldn't have,
so calls that wouldn't have been shown as missed were.

Remove the csutom call state and just have the missed state as a
variant of the ended state. Re-order the if clauses so they hit the
right ones. Also don't pass the callState variable into renderContent()
which is a class method and so has access to the same info anyway.