Create an account should set username as alias by default (shouldn't be empty)

changed milestone to %Itération 21

added 1 deleted label

Also if the Displayname/alias is the same as the username, it should be the only line shown

assigned to @mzhang

changed milestone to %Itération 21

https://review.jami.net/c/jami-client-qt/+/15892

added SprintTo review ~266 labels

mentioned in commit be1419c0