MM-30970 Add Basic unreadMentions support for collapsed threads (#16407)

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

app/user.go

@@ -2384,9 +2384,9 @@ func (a *App) GetThreadsForUser(userId string, options model.GetUserThreadsOpts)
 }
 
 func (a *App) UpdateThreadsReadForUser(userId string, timestamp int64) *model.AppError {
-	err := a.Srv().Store.Thread().MarkAllAsRead(userId, timestamp)
-	if err != nil {
-		return model.NewAppError("UpdateThreadsReadForUser", "app.user.update_threads_read_for_user.app_error", nil, err.Error(), http.StatusInternalServerError)
+	nErr := a.Srv().Store.Thread().MarkAllAsRead(userId, timestamp)
+	if nErr != nil {
+		return model.NewAppError("UpdateThreadsReadForUser", "app.user.update_threads_read_for_user.app_error", nil, nErr.Error(), http.StatusInternalServerError)
 	}
 	message := model.NewWebSocketEvent(model.WEBSOCKET_EVENT_THREAD_READ_CHANGED, "", "", userId, nil)
 	message.Add("timestamp", timestamp)
@@ -2395,7 +2395,7 @@ func (a *App) UpdateThreadsReadForUser(userId string, timestamp int64) *model.Ap
 }
 
 func (a *App) UpdateThreadFollowForUser(userId, threadId string, state bool) *model.AppError {
-	err := a.Srv().Store.Thread().CreateMembershipIfNeeded(userId, threadId, state)
+	err := a.Srv().Store.Thread().CreateMembershipIfNeeded(userId, threadId, state, false, true)
 	if err != nil {
 		return model.NewAppError("UpdateThreadFollowForUser", "app.user.update_thread_follow_for_user.app_error", nil, err.Error(), http.StatusInternalServerError)
 	}
@@ -2407,9 +2407,9 @@ func (a *App) UpdateThreadFollowForUser(userId, threadId string, state bool) *mo
 }
 
 func (a *App) UpdateThreadReadForUser(userId, threadId string, timestamp int64) *model.AppError {
-	err := a.Srv().Store.Thread().MarkAsRead(userId, threadId, timestamp)
-	if err != nil {
-		return model.NewAppError("UpdateThreadReadForUser", "app.user.update_thread_read_for_user.app_error", nil, err.Error(), http.StatusInternalServerError)
+	nErr := a.Srv().Store.Thread().MarkAsRead(userId, threadId, timestamp)
+	if nErr != nil {
+		return model.NewAppError("UpdateThreadReadForUser", "app.user.update_thread_read_for_user.app_error", nil, nErr.Error(), http.StatusInternalServerError)
 	}
 	message := model.NewWebSocketEvent(model.WEBSOCKET_EVENT_THREAD_READ_CHANGED, "", "", userId, nil)
 	message.Add("thread_id", threadId)