Multiuser plugin, creating unnecessary identities even i have not requested this

### Step 1: Please describe your environment

* ZeroNet version: 4473
* Operating system: W10 and Raspbian
* Web browser: FF
* Special configuration: Multiuser plugin

### Step 2: Describe the problem:

I think Multiuser plugin is creating identities that i have not requested. In my users.json file i found 3222 times phrase: "master_seed": "
On my new ZN instance, i found it 9 times and the "Change account:" prompt on ZeroHello shows only 6 accounts to choose from.
The /Stats page does not show any information about the users.json content so i can see which identity has how many sites, made how many posts or such. Or even the button to delete the identity - but that would be better for some identity manager/switcher GUI - current identity switcher not good when you have many identities - you can not see it on one page and search thru it.

Can the plugin be fixed so it does not create unnecessary identities at the first place?

I am asking because i was bothered with unreliability of the Multiuser plugin (it changing my identity from time to time) so i disabled it (just by renaming its directory) on my new instance where is 9 identities, but Zeronet was not starting without any indication in the log files. So i guess i have to somehow manually edit the users.json file and discover which identity to leave, but i do not remember where i posted or such to pick right identity "block" to leave.

Comienza reproduciendo el comportamiento del plugin Multiuser e inspeccionando users.json junto con el aviso Change account, la página /Stats y los registros de inicio. Determina por qué las identidades se crean o seleccionan de forma inesperada y, a continuación, verifica que desactivar el plugin y gestionar las identidades existentes ya no impida el inicio ni oculte la información de la cuenta.

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