Fix new DMs not showing up in the sidebar (#4374)

webapp/utils/channel_utils.jsx

@@ -35,7 +35,7 @@ export function buildDisplayableChannelList(persistentChannels) {
         publicChannels: notFavoriteChannels.filter(isOpenChannel),
         privateChannels: notFavoriteChannels.filter(isPrivateChannel),
         directChannels: directChannels.filter(isConnectedToTeamMember),
-        directNonTeamChannels: directChannels.filter(not(isConnectedToTeamMember))
+        directNonTeamChannels: directChannels.filter(isNotConnectedToTeamMember)
     };
 }
 
@@ -119,6 +119,10 @@ function isTeamMember(userId) {
     return TeamStore.hasActiveMemberInTeam(TeamStore.getCurrentId(), userId);
 }
 
+function isNotConnectedToTeamMember(channel) {
+    return TeamStore.hasMemberNotInTeam(TeamStore.getCurrentId(), channel.teammate_id);
+}
+
 function not(f) {
     return (...args) => !f(...args);
 }