Description

Steps to reproduce:

1. Go to https://wikifunctions.beta.wmflabs.org/wiki/Special:CreateZObject
2. Add a new alias label
3. Delete the alias label (so there are none)
4. Click ' + add alias'

(Note: This is the same behavior for existing zobjects if you delete all alias labels and try to add another)

Observed behavior:

1. See that you do not receive an alias input box when you try to re-add an alias.
2. The zobject tree adds a whole new Z31 object every time you click 'add alias'.

• ...

Expected behavior (Acceptance criteria):
The behavior should be the same as from the start - you should receive an input box when you click 'add alias', and the zobject tree should add new labels to the Z31K2 list.

• ...

Devices and Design (URLs or screenshots, if applicable):

• Desktop: ...
• Small screens/mobile: ...

Completion checklist

• Before closing this task, review one by one the checklist available here: https://www.mediawiki.org/wiki/Abstract_Wikipedia_team/Definition_of_Done#Front-end_Task/Bug_Completion_Checklist