After press Backspace key, language settings should not be saved

[RenBabiuch]

Description:
When the user makes changes to selected/deselected languages of the songs and presses 'Backspace' key (instead of approve choice by yellow confirm button), then the language settings should not be saved - especially if all languages are deselected.

Steps to reproduce:

1. Enter the game
2. Choose any input type or skip it
3. Go to sing a song (user will be automatically taken to select the language of the song first)
4. Deselect all possible song languages
5. Press 'Backspace' key
6. Go back to language settings by clicking: Manage songs -> Select song languages

Expected behaviour:
The 'Backspace' key should ensure that languages selected/deselected by the user are not saved - the default settings should be visible instead (before making any changes). The user shouldn't go to the Song list without pick at least 1 language.

Current behaviour:
The user's language settings are saved, so they can deselect all languages and go to the song list, even if it is not allowed (alert: 'You excluded all the languages, pick at least one')