MM-60124-emit and read create scheduled post WS event (#28844)

* MM-60124-emit and read create scheduled post WS event

* fix unit test; reorder get team id logic; use userid for ws events

* MM-60145 - ws events on update scheduled posts (#28871)

* MM-60145 - ws events on update scheduled posts

* MM-60147 - ws events on delete scheduled posts (#28872)

* MM-60147 - ws events on delete scheduled posts

* remove unnecessary channelID

* remove unnecesary memoization

server/public/model/websocket_message.go

@@ -91,6 +91,9 @@ const (
 	WebsocketEventChannelBookmarkSorted               WebsocketEventType = "channel_bookmark_sorted"
 	WebsocketPresenceIndicator                        WebsocketEventType = "presence"
 	WebsocketPostedNotifyAck                          WebsocketEventType = "posted_notify_ack"
+	WebsocketScheduledPostCreated                     WebsocketEventType = "scheduled_post_created"
+	WebsocketScheduledPostUpdated                     WebsocketEventType = "scheduled_post_updated"
+	WebsocketScheduledPostDeleted                     WebsocketEventType = "scheduled_post_deleted"
 )
 
 type WebSocketMessage interface {