General: Disable WebEngine for Nix build testing

[micieslak]

Bug Report

Description

Currently we are able to build the application using Qt 5.15.8 and older gblic (compatible with older system) using Nix. However the app crashes on login attempt.

There is a chance that dependency on WebEngine is a source of problems.

The goal of this task is to prepare modified version of the app with WebEngine disabled (not initialized or cut-off completely).

[yakimant]

You can do it in a separate branch or directly in PR:
#9232

This is how build dependencies are described in Nix:
https://github.com/status-im/status-desktop/blob/54ae166e25bdf597751170e2dd1fb21d843973c0/shell.nix

CI job for Nix build:
https://ci.status.im/job/status-desktop/job/systems/job/linux/job/x86_64/job/package_nix/
It doesn't run automatically. Need to "build with parameters" and choose ci/nix-shell branch.