MM-23816: Group Mentions: Add ability to rename group names (#14338)

* MM-23816: Group Mentions: Add ability to rename group names

model/user.go

@@ -25,6 +25,7 @@ import (
 const (
 	ME                                 = "me"
 	USER_NOTIFY_ALL                    = "all"
+	USER_NOTIFY_HERE                   = "here"
 	USER_NOTIFY_MENTION                = "mention"
 	USER_NOTIFY_NONE                   = "none"
 	DESKTOP_NOTIFY_PROP                = "desktop"