Translations are not exported

Problem/Motivation

The strings can't be translated on localize.drupal.org as they are not exported correctly with potx.

The strings are using translation context set in class constructor, like
$this->translationContext = 'shs:options_widget';

Due to the missing context the strings are not translated, even the same string (like "Add another item") is translated on l.d.o.

Steps to reproduce

Proposed resolution

Remove translation context or add it directly as a parameter to the t() function.

Remaining tasks

User interface changes

API changes

Data model changes