Check if `env_mobile` directive condition is supported by extensions on mobile devices

[Alex-302]

Prerequisites

Please answer the following questions for yourself before submitting an issue. YOU MAY DELETE THE PREREQUISITES SECTION.

• [x] I am running the latest version
• [x] I checked the documentation and found no answer
• [x] I checked to make sure that this issue has not already been filed

Problem Description

Related to https://github.com/gorhill/uBlock/wiki/Static-filter-syntax#if-condition Some rules must be limited by platform type, but extension(Chrome/FF) can be used on mobile devices.