refactor(radio-group0: use correct id

Author: thetaPC

core/src/components/radio-group/test/validation/index.html

@@ -108,7 +108,7 @@ <h2>Optional Field (No Validation)</h2>
         'fruits-radio-group': (value) => {
           return value !== undefined;
         },
-        'optional-checkbox': () => true, // Always valid
+        'optional-radio-group': () => true, // Always valid
       };
 
       function validateField(radioGroup) {