Language names not shown in settings page

Environment

• OS version: Ubuntu 20.04
• Browser version: Chrome 91
• Extension version: Adblock Plus 3.11
• Last working version: Adblock Plus 3.10.2

Steps to reproduce

Open desktop settings page.

Observed behavior

In "Language" section, filter list is shown as "EasyList (EasyList)".

Expected behavior

In "Language" section, filter list is shown as "English (EasyList)".

Further information

This regression was introduced in #939 (closed).

Hints for testers

This fix includes some refactoring. Therefore the following parts of the desktop settings page should also be checked, because they are related to the title resolution logic:

• The subscription title should be correctly displayed throughout the page:
  • In General tab:
    • In "Recommended filters" section
    • In "Language filter lists" section (both in languages list and drop down list)
    • In "More filter lists" section
  • In Advanced tab:
    • In "Filter lists" section (both in table and drop down list)
• Filters should be correctly displayed in the "Allowlisted websites" tab.
• The correct title should be shown also when setting or changing a filter list's title:
  • It can be set when adding a custom filter list via subscribe links.
  • It can change after downloading a newer version of the filter list.
• The option labels should be correctly displayed in the "Customizations" section.