Add Firefox Preview Nightly for Developers to the list of browsers

[superlex]

Currently, premium is required to block ads there:
https://play.google.com/store/apps/details?id=org.mozilla.fenix.nightly

(My AG version: AG for Android v.3.31)

[TheHasagi]

@superlex

Unfortunately, this browser does not accept our certificate and HTTPS can not be filtered by AdGuard properly.

[superlex]

@TheHasagi
Yep, I know, but maybe it could be added to the known browser's list anyway.
See #2958

Btw, if you prefer to wait its certificate support, it's ok.

[ameshkov]

@superlex sure, it should be added to the browsers list, but marked as not supporting HTTPS filtering (just like Opera for instance).

[superlex]

@ameshkov
Yes, like Firefox Preview (org.mozilla.fenix) :)
Thanks