Adapt code to work with removed Subscription.prototype.filters

Background

See trac#7308.

What to change

• Replace Subscription.filters() in mock
• Replace calls to Subscription.filters() in lib/*.js files
• Check that there's no change in the data the various UI pages receive from the background page
• Update https://gitlab.com/eyeo/adblockplus/abpui/adblockpluscore and https://gitlab.com/eyeo/adblockplus/abpui/adblockpluschrome accordingly

Hints for testers

• Anti-adblock notification should be shown when visiting a URL that matches one of its filters (see URL filters).
• When loading, adding (incl. copy-pasting into the UI), modifying or removing custom filters, they should be displayed accordingly in the desktop options page.
• The number of disabled filters should be listed accordingly in the issue report data (e.g. <subscription disabledFilters="12"/>).