Achievements: Avoid potential crash when parsing malformed responses

src/frontend-common/achievements.cpp

@@ -256,7 +256,7 @@ public:
     data.push_back(0);
 
     const int error = ParseFunc(this, reinterpret_cast<const char*>(data.data()));
-    initialized = true;
+    initialized = (error == RC_OK);
 
     const rc_api_response_t& response = static_cast<T*>(this)->response;
     if (error != RC_OK)