Fix errors showing up from invalid public chats

js/modules/loki_app_dot_net_api.js

@@ -987,7 +987,9 @@ class LokiPublicChannelAPI {
 
     // sort pending messages by if slave device or not
     /* eslint-disable no-param-reassign */
-    const slaveMessages = pendingMessages.reduce((retval, messageData) => {
+    const slaveMessages = pendingMessages
+      .filter(messageData => !!messageData)
+      .reduce((retval, messageData) => {
         // if a known slave, queue
         if (slavePrimaryMap[messageData.source]) {
           // delay sending the message