When joining a group from a link for second time, I seem to join a second time.

What happend:
I joined a Deltachatroom from a link on a website https://wiki.why2025.org/Session:Try_Delta_Chat_decentral_email-based_chat

Client tells me "Member Me added by ..."

Later clicked the link again, client tells me "Member Me added by ..." But I was already there.

**Expected to happen: **
When clicking an invite link for a second time, client should tell me 'you're allready a member of ....'

(Is a minor UX issue not a big problem.)

[iequidoo]

Should be done in https://github.com/chatmail/core (but the issue may stay here). Maybe just not add "Member Me added by..." if it's no-op? The chat opens, you can see that you're a member, this should be enough.