Simplify security samples

As of gh-81, specific security components are contributed by the
GraphQL Security auto-configuration.

This commit removes those from the custom SecurityConfig classes.

samples/webflux-security/src/main/java/io/spring/sample/graphql/SecurityConfig.java

@@ -17,7 +17,6 @@ package io.spring.sample.graphql;
 
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
-import org.springframework.graphql.security.ReactiveSecurityDataFetcherExceptionResolver;
 import org.springframework.security.config.annotation.method.configuration.EnableReactiveMethodSecurity;
 import org.springframework.security.config.annotation.web.reactive.EnableWebFluxSecurity;
 import org.springframework.security.config.web.server.ServerHttpSecurity;
@@ -53,9 +52,4 @@ public class SecurityConfig {
 		return new MapReactiveUserDetailsService(rob, admin);
 	}
 
-	@Bean
-	public ReactiveSecurityDataFetcherExceptionResolver dataFetcherExceptionResolver() {
-		return new ReactiveSecurityDataFetcherExceptionResolver();
-	}
-
 }