PLT-5211 Always emove deleted channels for LHS (#5087)

webapp/utils/channel_utils.jsx

@@ -23,7 +23,7 @@ import LocalizationStore from 'stores/localization_store.jsx';
 export function buildDisplayableChannelList(persistentChannels) {
     const missingDMChannels = createMissingDirectChannels(persistentChannels);
 
-    const channels = persistentChannels.concat(missingDMChannels).map(completeDirectChannelInfo);
+    const channels = persistentChannels.concat(missingDMChannels).map(completeDirectChannelInfo).filter(isNotDeletedChannel);
     channels.sort(sortChannelsByDisplayName);
 
     const favoriteChannels = channels.filter(isFavoriteChannel);
@@ -43,6 +43,10 @@ export function isFavoriteChannel(channel) {
     return PreferenceStore.getBool(Preferences.CATEGORY_FAVORITE_CHANNEL, channel.id);
 }
 
+export function isNotDeletedChannel(channel) {
+    return channel.delete_at === 0;
+}
+
 export function isOpenChannel(channel) {
     return channel.type === Constants.OPEN_CHANNEL;
 }