Switched UI Label to use localized strings.

src/dawn/asset/assets/LanguageAsset.cpp

@@ -72,6 +72,8 @@ void LanguageAsset::updateAsync() {
 
 std::string LanguageAsset::getValue(std::string key) {
   assertTrue(this->state == 0x07);
+  assertMapHasKey(this->values, key);
+  assertTrue(this->values[key].begin >= 0 && this->values[key].length > 0);
 
   // Get the positions
   struct AssetLanguageValue value = this->values[key];