Discourse may bypass user preference when adding users to chat groups

Discourse is an open-source discussion platform. Prior to versions `3.3.4` on the `stable` branch and `3.4.0.beta5` on the `beta` branch, in specific circumstances, users could be added to group direct messages despite disabling direct messaging in their preferences. Versions `3.3.4` and `3.4.0.beta5` contain a patch for the issue. A workaround is available. If a user disables chat in their preferences then they cannot be added to new group chats.