fix(cors): restrict allowed headers in CORS configuration

backend/src/main/java/de/szut/casino/config/CorsConfig.java

@@ -11,7 +11,7 @@ public class CorsConfig implements WebMvcConfigurer {
         registry.addMapping("/**")
                 .allowedOrigins("http://localhost:4200", "http://192.168.176.120:4200")
                 .allowedMethods("GET", "POST", "PUT", "DELETE", "OPTIONS")
-                .allowedHeaders("*")
+                .allowedHeaders("Origin", "Content-Type", "Accept", "Authorization", "X-Requested-With")
                 .allowCredentials(true)
                 .maxAge(3600);
     }