Bug Description

For epubs such as the example in #1367 where UND is defined as the language, the translate icon on the toolbar is activated even if the translate function is disabled in the settings.

Expected behavior

Icon should not turn on for UND (or for any languages that are not available in the translator) if translate is turned off in the settings.

Technical inputs

Operating System: Android 9

Readest Version: 0.9.59 and earlier