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.

Start by reproducing the Multiuser plugin behavior and inspecting users.json alongside the Change account prompt, /Stats page, and startup logs. Determine why identities are created or selected unexpectedly, then verify that disabling the plugin and managing existing identities no longer prevents startup or hides account information.

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