Summary: After this change you can lurk in public chats, and receive notifications, without crashing your planet. Fix exception "Undefined index: PHID-USER-..." shown to newcomers when they are receiving messages from a public Chat they are not members of. Closes T15497 Test Plan: - Have the Notification server (Aphlict) enabled and running. https://we.phorge.it/book/phorge/article/notifications/ - Be user Alice and visit a Conpherence Room. Alice must be not a participant. - Be user Bob and send a message in that Room. Now Alice does not see a crash anymore, but the message from Bob. Reviewers: O1 Blessed Committers, speck Reviewed By: O1 Blessed Committers, speck Subscribers: speck, tobiaswiese, Matthew, Cigaryno Maniphest Tasks: T15497 Differential Revision: https://we.phorge.it/D25408