MM-37896: thread recency when updating a post (#18363)

When a post is edited we should not update the thread recency
(LastReplyAt).

store/sqlstore/post_store.go

@@ -357,7 +357,6 @@ func (s *SqlPostStore) Update(newPost *model.Post, oldPost *model.Post) (*model.
 
 	if newPost.RootId != "" {
 		s.GetMaster().Exec("UPDATE Posts SET UpdateAt = :UpdateAt WHERE Id = :RootId AND UpdateAt < :UpdateAt", map[string]interface{}{"UpdateAt": time, "RootId": newPost.RootId})
-		s.GetMaster().Exec("UPDATE Threads SET LastReplyAt = :UpdateAt WHERE PostId = :RootId", map[string]interface{}{"UpdateAt": time, "RootId": newPost.RootId})
 	}
 
 	// mark the old post as deleted