Correlating anonymous user ID (meeting app context and bot)

I have the following problem: I'm creating a Teams meeting app that is supposed to be used by anonymous users that can join via meeting link using the web version of Microsoft Teams. The app is shared to the meeting stage by the organizer and is correctly displayed by anonymous users, but it seems that there's no way to correlate the user ID that is available through context from javascript SDK (that looks like this: 8:teamsvisitor:ecfffc40c0be492da74621ce52011a22) with the ID that the bot gets when OnTeamsMembersAdded event is fired for the same user (29:1AUqWyWMQciXXvShFEnTYUoM4-Efaw6WZZZFN3fOVdOpewtmkYUXwSgUr05hPs0dub1t7tqPw4b9t0r7G2k7zfA).

I need to call the backend service from Javascript, but it seems that using only the user ID from context and not being able to generate SSO token for the anonymous user from Teams web app, there's no way to know who is making the call, as the IDs available on frontend and backend side are totally different. Is there any method to map one ID to another or some other way to do it that I'm missing?

Here's the code I'm using to get the user's details from the TeamsMembersAdded event:

var members = await TeamsInfo.GetMembersAsync(turnContext, cancellationToken);
foreach (var member in members)
{
    var teamsParticipant = await TeamsInfo.GetMeetingParticipantAsync(turnContext, participantId: member.Id, cancellationToken: cancellationToken);
}