fix: avoid potential NPE

Author: metacosm

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/api/config/ConfigurationService.java

@@ -3,7 +3,10 @@
 import java.time.Duration;
 import java.util.Optional;
 import java.util.Set;
-import java.util.concurrent.*;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.LinkedBlockingDeque;
+import java.util.concurrent.ThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
 import java.util.function.Consumer;
 
 import org.slf4j.Logger;
@@ -252,8 +255,11 @@ default ResourceClassResolver getResourceClassResolver() {
 
   static ConfigurationService overrideCurrent(ConfigurationService service,
       Consumer<ConfigurationServiceOverrider> overrider) {
-    final var toOverride = new ConfigurationServiceOverrider(service);
-    overrider.accept(toOverride);
-    return toOverride.build();
+    if (overrider != null) {
+      final var toOverride = new ConfigurationServiceOverrider(service);
+      overrider.accept(toOverride);
+      return toOverride.build();
+    }
+    return service;
   }
 }