Automated cherry pick of #35269 (#35459)

* MM-67522 Add tests for syncing user statuses (#35269)

* MM-67522 Add tests for syncing user statuses

* Clean up newly added tests

* Fix style

* Use SyncResponse.StatusErrors when statuses fail to sync

(cherry picked from commit 033867a3448875d84653c81026d31bddf3ce4c40)

* Rename rctx to c

---------

Co-authored-by: Harrison Healey <harrisonmhealey@gmail.com>

server/platform/services/sharedchannel/sync_recv.go

@@ -263,7 +263,13 @@ func (scs *Service) processSyncMessage(c request.CTX, syncMsg *model.SyncMsg, rc
 	}
 
 	for _, status := range syncMsg.Statuses {
-		scs.app.SaveAndBroadcastStatus(status)
+		if err := scs.upsertSyncUserStatus(c, status, rc); err != nil {
+			scs.server.Log().Log(mlog.LvlSharedChannelServiceError, "Error upserting sync user status",
+				mlog.String("remote", rc.Name),
+				mlog.String("user_id", status.UserId),
+				mlog.Err(err))
+			syncResp.StatusErrors = append(syncResp.StatusErrors, status.UserId)
+		}
 	}
 
 	// Process membership changes after users have been synced
@@ -754,6 +760,26 @@ func (scs *Service) upsertSyncAcknowledgement(acknowledgement *model.PostAcknowl
 	return savedAcknowledgement, retErr
 }
 
+func (scs *Service) upsertSyncUserStatus(rctx request.CTX, status *model.Status, rc *model.RemoteCluster) error {
+	user, err := scs.server.GetStore().User().Get(rctx.Context(), status.UserId)
+	if err != nil {
+		return fmt.Errorf("error getting user when syncing status: %w", err)
+	}
+
+	if user.GetRemoteID() != rc.RemoteId {
+		scs.server.Log().Log(mlog.LvlSharedChannelServiceError, "RemoteID mismatch sync'ing user status",
+			mlog.String("remote", rc.Name),
+			mlog.String("user_id", status.UserId),
+			mlog.String("user_remote_id", user.GetRemoteID()),
+		)
+		return fmt.Errorf("error updating user status: %w", ErrRemoteIDMismatch)
+	}
+
+	scs.app.SaveAndBroadcastStatus(status)
+
+	return nil
+}
+
 // transformMentionsOnReceive transforms mentions in received posts using explicit mentionTransforms.
 func (scs *Service) transformMentionsOnReceive(rctx request.CTX, post *model.Post, targetChannel *model.Channel, rc *model.RemoteCluster, mentionTransforms map[string]string) {
 	if post.Message == "" || len(mentionTransforms) == 0 {