feat(notifications): provide a way to turn off sticky notifications (#4010)

interface_config.js

     /**
      * Specify the Android app package name.
      */
-    // ANDROID_APP_PACKAGE: 'org.jitsi.meet'
+    // ANDROID_APP_PACKAGE: 'org.jitsi.meet',
+
+    /**
+     * Override the behavior of some notifications to remain displayed until
+     * explicitly dismissed through a user action. The value is how long, in
+     * milliseconds, those notifications should remain displayed.
+     */
+    // ENFORCE_NOTIFICATION_AUTO_DISMISS_TIMEOUT: 15000,
 };
 
 /* eslint-enable no-unused-vars, no-var, max-len */

react/features/notifications/components/AbstractNotificationsContainer.js

      */
     _notifications: Array<Object>,
 
+    /**
+     * The length, in milliseconds, to use as a default timeout for all
+     * dismissable timeouts that do not have a timeout specified.
+     */
+    autoDismissTimeout: number,
+
     /**
      * Invoked to update the redux store in order to remove notifications.
      */
     dispatch: Function
 };
 
+declare var interfaceConfig: Object;
+
 /**
  * Abstract class for {@code NotificationsContainer} component.
  */
      * @private
      */
     _manageDismissTimeout(prevProps: ?P) {
-        const { _notifications } = this.props;
+        const { _notifications, autoDismissTimeout } = this.props;
 
         if (_notifications.length) {
             const notification = _notifications[0];
             if (notification !== previousNotification) {
                 this._clearNotificationDismissTimeout();
 
-                if (notification) {
-                    const { timeout, uid } = notification;
+                if (notification
+                        && (notification.timeout
+                            || typeof autoDismissTimeout === 'number')
+                        && notification.props.isDismissAllowed !== false) {
+                    const {
+                        timeout = autoDismissTimeout,
+                        uid
+                    } = notification;
 
                     this._notificationDismissTimeout = setTimeout(() => {
                         // Perform a no-op if a timeout is not specified.
-                        if (Number.isInteger(timeout)) {
-                            this._onDismissed(uid);
-                        }
+                        this._onDismissed(uid);
                     }, timeout);
                 }
             }
     const _visible = areThereNotifications(state);
 
     return {
-        _notifications: _visible ? notifications : []
+        _notifications: _visible ? notifications : [],
+        autoDismissTimeout: typeof interfaceConfig === 'undefined'
+            ? undefined // Ignore for the case of mobile
+            : interfaceConfig.ENFORCE_NOTIFICATION_AUTO_DISMISS_TIMEOUT
     };
 }