ios: remove no longer needed code

Ever since we switched to handling track events instead of mute actions this has
been dead code. It was also added in the wrong place, since it's responsibility
of the JS code to solve the ping-pong problem.

ios/sdk/src/callkit/JMCallKitEmitter.swift

 internal final class JMCallKitEmitter: NSObject, CXProviderDelegate {
 
     private var listeners = Set<JMCallKitEventListenerWrapper>()
-    private var pendingMuteActions = Set<UUID>()
 
     internal override init() {}
 
         }
     }
 
-    // MARK: - Add mute action
-
-    func addMuteAction(_ actionUUID: UUID) {
-        pendingMuteActions.insert(actionUUID)
-    }
-
     // MARK: - CXProviderDelegate
 
     func providerDidReset(_ provider: CXProvider) {
         listeners.forEach { $0.listener?.providerDidReset?() }
-        pendingMuteActions.removeAll()
     }
 
     func provider(_ provider: CXProvider, perform action: CXAnswerCallAction) {
     }
 
     func provider(_ provider: CXProvider, perform action: CXSetMutedCallAction) {
-        let uuid = pendingMuteActions.remove(action.uuid)
-
-        // XXX avoid mute actions ping-pong: if the mute action was caused by
-        // the JS side (we requested a transaction) don't call the delegate
-        // method. If it was called by the provder itself (when the user presses
-        // the mute button in the CallKit view) then call the delegate method.
-        if (uuid == nil) {
-            listeners.forEach {
-                $0.listener?.performSetMutedCall?(UUID: action.callUUID,
-                                                isMuted: action.isMuted)
-            }
+        listeners.forEach {
+            $0.listener?.performSetMutedCall?(UUID: action.callUUID, isMuted: action.isMuted)
         }
 
         action.fulfill()

ios/sdk/src/callkit/JMCallKitProxy.swift

             completion: @escaping (Error?) -> Swift.Void) {
         guard enabled else { return }
 
-        // XXX keep track of muted actions to avoid "ping-pong"ing. See
-        // JMCallKitEmitter for details on the CXSetMutedCallAction handling.
-        for action in transaction.actions {
-            if (action as? CXSetMutedCallAction) != nil {
-                emitter.addMuteAction(action.uuid)
-            }
-        }
-
         callController.request(transaction, completion: completion)
     }
 
         return update
     }
 }
-