Support for cap_html_filtering condition

[alexx7311]

Issue Details

Similar: AdguardTeam/AdguardBrowserExtension#2146

https://github.com/gorhill/uBlock/wiki/Static-filter-syntax#if-condition

Sometimes an annoyance or popup case can be dealt with by either removing the script from that page entirely (HTML filtering) or with the use of scriptlets and it makes sense that the scriptlet rules don't get injected into a page that HTML filtering has already been applied to.

So I use this in my list:

example.com##^script:has-text(BadStuff)
!#if !cap_html_filtering
example.com##+js(FirstScriptlet)
example.com##+js(SecondScriptlet)
example.com##+js(ThirdScriptlet)
!#endif

For AdGuard it can be translated into !#if (!adguard_app_windows && !adguard_app_mac && !adguard_app_android && !adguard_ext_firefox) but it makes sense to have a dedicated condition for this.

Proposed solution

!#if cap_html_filtering

Alternative solution

!#if (!adguard_app_windows && !adguard_app_mac && !adguard_app_android && !adguard_ext_firefox)

[alexx7311]

copy of #2259

[MasterKia]

@ameshkov:
AdguardTeam/AdguardBrowserExtension#2259 (comment)