Widgets throw error due to broken \LanguageServiceFactory::create()

Bug Report

Current Behavior
Using the extension in a multilanguage setup the dashboard gets unaccessible due to the lines

Line 32 in 257cea6

    
           $this->languageService = GeneralUtility::makeInstance(LanguageServiceFactory::class)->create($GLOBALS['BE_USER']->uc['lang']);

and

Line 31 in 257cea6

    
           $this->languageService = GeneralUtility::makeInstance(LanguageServiceFactory::class)->create($GLOBALS['BE_USER']->uc['lang']);

Expected behavior/output
Widget shall not lead to an error.

Environment

Possible Solution
The given code can be replaced with

$this->languageService = $GLOBALS['LANG'];

[BUGFIX] Widgets do not throw errors in dashboard

[BUGFIX] Use createFromUserPreferences for creating LanguageService

Should be fixed with #735 and #737.