fix: when decoding CSV, do not include empty fields as nodes

[nikaera]

When using CSV for translation files, if specific fields are empty, it can be assumed that the translation is not provided. Therefore, I made modifications to handle such cases accordingly. ✅

[Tienisto]

Could you please try the fallback_strategy: base_locale_empty_string configuration?
Your change might break others code if they actually expect an empty string.

[nikaera]

Thank you very much for the detailed explanation! Adding fallback_strategy: base_locale_empty_string to build.yaml as you suggested has resulted in the intended behavior! 🙌 @Tienisto