"group left" messages should not create/unarchive groups

[r10s]

these "group left" messages often come from unwanted group splits [^1], however, also on normal usage, it seems fine to not sort the group up - or even create or unarchive the group.

the info-message itself should be added as usual.

if avoiding sorting-up is difficult, at least unarchiving and creation should be avoided, this would already help a lot.

this can be done post-1.46, however, not super-urgent :)

[^1]: afaik, recent group split happen because group-id was removed from message-id and download-on-demand-bug has a buggy fallback; this is fixed/mitigated on the sender side - but the receiver still gets splitted groups that ppl leave over and over, each time recreating a just deleted group

[iequidoo]

I'm not sure about not sorting up, but agree with wrt group unarchiving and creation. If i added someone to a group then it may be interesting to me that they have left the group. Though not sorting up isn't difficult at all -- we can just use the sort timestamp of the previous message for the "group left" one.

[r10s]

yeah, then let's skip the not-sort-up, this is probably not worth the effort

let's go for not-create, not-unarchive, that probably makes things already a loooot better :)