Horizon: Silent error "Content too large" & "Invalid size" of the data.json

### Step 1: Please describe your environment

* ZeroNet version: 3597
* Operating system: Linux
* Web browser: FF
* Tor status: always
* Opened port: no

### Step 2: Describe the problem:

In [this comment](https://github.com/blurHY/Horizon/issues/12#issuecomment-423489989) i was invited to submit this issue. [Horizon](http://127.0.0.1:43110/1CjMsvhJ2JsV4B5qo3FDHnF3mvRCcHuxBn/) site is downloaded, but it had problem with "Content too large" & "Invalid size" of the data.json but this issue was silent (in debug.log).