💻Don't autoselect level 1 when creating a custom adventure

[AnneliesVlaar]

When creating a custom adventure, available in level 1 is automatically selected. when creating an adventure which is not available in level 1, you need to deselect level 1 and select the correct level.
Suggested behavior: there is no level selected and the placeholder text ('Select levels') is displayed.

[AnneliesVlaar]

There is also a 'Select all' (levels) option, I haven't been able to think of an adventure that is suitable for all levels. Is this option redundant?

[AnneliesVlaar]

The same might be true for selecting the language. 'English' is by default selected as the language of the adventure.