[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

model/channel.go

@@ -67,8 +67,8 @@ type ChannelWithTeamData struct {
 }
 
 type ChannelsWithCount struct {
-	Channels   *ChannelListWithTeamData `json:"channels"`
-	TotalCount int64                    `json:"total_count"`
+	Channels   ChannelListWithTeamData `json:"channels"`
+	TotalCount int64                   `json:"total_count"`
 }
 
 type ChannelPatch struct {