Language selection in Updater no longer works

[sgiehl]

Context

When a database update is required Matomo displays an update screen. By default the screen uses the browser language.

There is also a language drop down, which should allow to change the language of the screen.

Selecting another language, currently tries to save the selected language by posting a form to index.php?module=LanguagesManager&action=saveLanguage

As the updater might be performed without a session or login, this can result in an error screen, asking to login.

Expected Behavior

The language of the update screen can simply be changed by using the parameter &language=XX, so when choosing another language the parameter in url should be change/added.

Steps to Reproduce (for Bugs)

1. Force update screen to display by changing the option value for version_Core to a value like 4.14.0
2. Open Matomo
3. Try to select another language

Your Environment

• Matomo Version: 5.0.0-b4
• PHP Version: 7.2
• Server Operating System: Linux