Fix issue when reading locale in old HA versions

[AitorDB]

Some old Home assistant versions doesn't provide the locale property, this causes the card to crash by trying to access properties inside locale when it's undefined

[github-actions[bot]]

🎉 HACS repository validator action summary 🎉 ✅ The repository is not archived ✅ hacs.json has the 'name' key set ✅ The repository has a description ✅ The repository has topics ✅ The repository has issues enabled ✅ This day ends with an 'y' (Monday) ✅ README.md exists ✅ Information file has images ✅ HACS load check