Some adjustments

Author: DanielSchiavo

mongock-core/mongock-runner/spring/springboot/mongock-springboot/src/test/java/io/mongock/runner/springboot/mongockscanpackage/ModuleConfigMongockScanPackage.java

@@ -18,7 +18,7 @@ public void add(String packageName) {
   }
 
   public void addAll(List<String> packageNames) {
-    if (!packageNames.isEmpty()) {
+    if (packageNames != null && !packageNames.isEmpty()) {
       builder.addMigrationScanPackages(packageNames);
     }
   }