Default value check is too greedy and raises issues in practice

[otacke]

In

https://github.com/h5p/h5p-cli/blob/b2667b3b044a048c11aa933685beca4605439dac/assets/utils/h5p.js#L1021-L1023

default fields that contain one of the language codes only will be purged. This is too greedy and also hits the simple English word "No" that happens to occur in GameMap as a translatable word, cmp. https://github.com/otacke/h5p-game-map/blob/master/semantics.json#L1065