Pack name and description display the translation key instead of falling back on English (US)

Expected behavior

Resource packs fall back to use the English (US) translations if their current language is unsupported by the resource pack (language not listed in texts/languages.json and no dedicated .lang file) as they did in versions before 26.60.

Actual behavior

Resource packs display the translation key for the pack name and pack description instead of falling back to English (US).

Steps to reproduce:

1. Install the attached Minecraft resource pack.

2. Switch your language to English (US) if you haven’t yet.

3. Activate the resource pack in global resource packs, notice how the pack name and description are displayed as intended.

4. Change your language to English (GB) or any other language.

5. Go back to global resource packs, notice how the pack name and description display their translation keys instead of falling back to English (US).