Notification : clean the string text

### Step 1: Please describe your environment

* ZeroNet version: rev4086
* Operating system: Ubuntu
* Web browser: Firefox
* Tor status: not available
* Opened port: yes
* Special configuration: None
### Step 2: Describe the problem:

Notification show a small text but it could be cleaned from unnecessary characters...
see screenshot


#### Expected Results:

Don't show ` ` but show a space instead.

Reproduce the notification in the reported Ubuntu and Firefox environment and inspect the rendered text shown in the screenshot. Done means the notification displays a normal space instead of the literal ` ` text.

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