Exception thrown in BigBlueButtonActor on handleChangeUserEmojiCmdMsg

[kepstin]

Describe the bug
On a relatively long running BigBlueButton 2.6 server, I'm seeing occasional reports of an exception being thrown in BigBlueButtonActor, in the method org.bigbluebutton.core.apps.users.ChangeUserEmojiCmdMsgHdlr.handleChangeUserEmojiCmdMsg:

2023-08-16T06:06:41.649Z ERROR o.b.core.BigBlueButtonActor - An exception has been thrown on BigBlueButtonActor, exception message [None.get] (full stacktrace below)
java.util.NoSuchElementException: None.get
        at scala.None$.get(Option.scala:627)
        at scala.None$.get(Option.scala:626)
        at org.bigbluebutton.core.apps.users.ChangeUserEmojiCmdMsgHdlr.handleChangeUserEmojiCmdMsg(ChangeUserEmojiCmdMsgHdlr.scala:31)
        at org.bigbluebutton.core.apps.users.ChangeUserEmojiCmdMsgHdlr.handleChangeUserEmojiCmdMsg$(ChangeUserEmojiCmdMsgHdlr.scala:14)
        at org.bigbluebutton.core.running.MeetingActor.handleChangeUserEmojiCmdMsg(MeetingActor.scala:62)
        at org.bigbluebutton.core.running.MeetingActor.handleMessageThatAffectsInactivity(MeetingActor.scala:388)
        at org.bigbluebutton.core.running.MeetingActor.org$bigbluebutton$core$running$MeetingActor$$handleBbbCommonEnvCoreMsg(MeetingActor.scala:358)
        at org.bigbluebutton.core.running.MeetingActor$$anonfun$receive$1.applyOrElse(MeetingActor.scala:248)
        at akka.actor.Actor.aroundReceive(Actor.scala:537)
        at akka.actor.Actor.aroundReceive$(Actor.scala:535)
        at org.bigbluebutton.core.running.MeetingActor.aroundReceive(MeetingActor.scala:62)
        at akka.actor.ActorCell.receiveMessage(ActorCell.scala:580)
        at akka.actor.ActorCell.invoke(ActorCell.scala:548)
        at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:270)
        at akka.dispatch.Mailbox.run(Mailbox.scala:231)
        at akka.dispatch.Mailbox.exec(Mailbox.scala:243)
        at java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:290)
        at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1020)
        at java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1656)
        at java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1594)
        at java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:183)
2023-08-16T06:06:41.649Z WARN  akka.actor.OneForOneStrategy - None.get

It seems like the user lookup in https://github.com/bigbluebutton/bigbluebutton/blob/v2.6.x-release/akka-bbb-apps/src/main/scala/org/bigbluebutton/core/apps/users/ChangeUserEmojiCmdMsgHdlr.scala#L31 is failing, but it's unclear why.

To Reproduce
The exact reproduction steps aren't known. We haven't had any reports from users about problems with the emoji selector.