Language always falls back to default language

Problem/Motivation

No matter what langcode is set in StoryChief, the Drupal node always ends up in the default language.

Steps to reproduce

Create a post in a non-default language in StoryChief and submit it to Drupal.

Proposed resolution

In LanguageStoryChiefFieldHandler::getValue(), parent::getValue() always returns NULL. This happens because BaseFieldHandlerType::$value is private, which means LanguageStoryChiefFieldHandler can't access its value. Changing BaseFieldHandlerType::$value to protected fixes this.

Remaining tasks

User interface changes

API changes

Data model changes