Android/iOS leave notifications until channel is read (#2321)

* iOS clear notifications from a specific channel when clear push notification received

* Android leave notifications until channel is read

* use redux-connect currentChannelId in network indicator

android/app/src/main/java/com/mattermost/rnbeta/CustomPushNotificationDrawer.java

@@ -0,0 +1,39 @@
+package com.mattermost.rnbeta;
+
+import android.content.Context;
+
+import com.wix.reactnativenotifications.core.AppLaunchHelper;
+import com.wix.reactnativenotifications.core.notificationdrawer.PushNotificationsDrawer;
+import com.wix.reactnativenotifications.core.notificationdrawer.IPushNotificationsDrawer;
+import com.wix.reactnativenotifications.core.notificationdrawer.INotificationsDrawerApplication;
+import com.wix.reactnativenotifications.helpers.PushNotificationHelper;
+import static com.wix.reactnativenotifications.Defs.LOGTAG;
+
+public class CustomPushNotificationDrawer extends PushNotificationsDrawer {
+    final protected Context mContext;
+    final protected AppLaunchHelper mAppLaunchHelper;
+
+   protected CustomPushNotificationDrawer(Context context, AppLaunchHelper appLaunchHelper) {
+        super(context, appLaunchHelper);
+        mContext = context;
+        mAppLaunchHelper = appLaunchHelper;
+    }
+
+    @Override
+    public void onAppInit() {
+    }
+
+    @Override
+    public void onAppVisible() {
+    }
+
+    @Override
+    public void onNotificationOpened() {
+    }
+
+    @Override
+    public void onCancelAllLocalNotifications() {
+        CustomPushNotification.clearAllNotifications(mContext);
+        cancelAllScheduledNotifications();
+    }
+}