Reconcile audio and video enabling with call state.

// FREEBIE

Signal/src/call/CallService.swift

@@ -911,8 +911,10 @@ protocol CallServiceObserver: class {
             return
         }
 
+        if call.state == .connected {
             peerConnectionClient.setAudioEnabled(enabled: !isMuted)
         }
+    }
 
     /**
      * Local user toggled video.
@@ -966,8 +968,10 @@ protocol CallServiceObserver: class {
             return
         }
 
+        if call.state == .connected {
             peerConnectionClient.setLocalVideoEnabled(enabled: shouldHaveLocalVideoTrack())
         }
+    }
 
     func handleCallKitStartVideo() {
         AssertIsOnMainThread()