Key-contacts migration converts a group to adhoc group because of past members

[link2xt]

I have a group where a member was just removed because it does not have a key. The group is encrypted, but when I transfer an account to the new version, group gets converted to adhoc group with a generic avatar and grpid erased.

It should be fine to forget this past member and convert the group to an encrypted group with a grpid instead. For group consistency after migration either everyone forgets this past member or someone knows the key and will convert it to a past member with the key.

Marked as blocker because it should be fixed before releasing the new core, we will not be able to redo the migration again.

During migration, this line is printed:

src/sql/migrations.rs:1633: Chat 249 will be an unencrypted chat with contacts identified by email address: Group contains contact without peerstate

[iequidoo]

Self-assigning, but feel free to steal. CC @Hocuri