Merge pull request #40963 from quaff

* pr/40963:
  Remove unnecessary null check

Closes gh-40963

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/context/properties/source/ConfigurationPropertySources.java

@@ -87,7 +87,7 @@ public final class ConfigurationPropertySources {
 		Assert.isInstanceOf(ConfigurableEnvironment.class, environment);
 		MutablePropertySources sources = ((ConfigurableEnvironment) environment).getPropertySources();
 		PropertySource<?> attached = getAttached(sources);
-		if (attached == null || !isUsingSources(attached, sources)) {
+		if (!isUsingSources(attached, sources)) {
 			attached = new ConfigurationPropertySourcesPropertySource(ATTACHED_PROPERTY_SOURCE_NAME,
 					new SpringConfigurationPropertySources(sources));
 		}