Conditional on bean name for dgsAsyncTaskExecutor

Check for bean name in the conditional for the virtualThreadTaskExecutor. Otherwise it will match on any AsyncTaskExecutor, which comes out of the box with spring.

graphql-dgs-spring-boot-oss-autoconfigure/src/main/kotlin/com/netflix/graphql/dgs/autoconfig/DgsAutoConfiguration.kt

@@ -312,7 +312,7 @@ open class DgsAutoConfiguration(
     @Bean
     @Qualifier("dgsAsyncTaskExecutor")
     @ConditionalOnJava21
-    @ConditionalOnMissingBean
+    @ConditionalOnMissingBean(name = ["dgsAsyncTaskExecutor"])
     @ConditionalOnProperty(name = ["dgs.graphql.virtualthreads.enabled"], havingValue = "true", matchIfMissing = false)
     open fun virtualThreadsTaskExecutor(): AsyncTaskExecutor {
         LOG.info("Enabling virtual threads for DGS")