[MM-28985] Remove pointers to slice (part 1) (#18034)

* Remove pointers to slice (part 1)

* Remove use of pointers to slice from model package (#18045)

* Fix after merge

store/searchlayer/user_layer.go

@@ -171,7 +171,7 @@ func (s *SearchUserStore) getListOfAllowedChannelsForTeam(teamId string, viewRes
 		if err != nil {
 			return nil, errors.Wrap(err, "failed to get team channels")
 		}
-		for _, channel := range *channels {
+		for _, channel := range channels {
 			listOfAllowedChannels = append(listOfAllowedChannels, channel.Id)
 		}
 		return listOfAllowedChannels, nil