GH-345 - Properly handle manually declared entity scan and autoconfiguration packages.

If Spring Modulith packages were explicitly configured as autoconfiguration or entity scan packages, the test autoconfiguration would fail as it previously attempted to manipulate an immutable list. We now create a copy of that list to fix this.

spring-modulith-test/src/main/java/org/springframework/modulith/test/ModuleTestAutoConfiguration.java

@@ -15,6 +15,7 @@
  */
 package org.springframework.modulith.test;
 
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 
@@ -72,14 +73,15 @@ class ModuleTestAutoConfiguration {
 				return;
 			}
 
+			var packagesToSet = new ArrayList<>(packages);
 			var definition = registry.getBeanDefinition(beanName);
 			var holder = definition.getConstructorArgumentValues().getArgumentValue(0, String[].class);
 
 			Arrays.stream((String[]) holder.getValue())
 					.filter(it -> it.startsWith("org.springframework.modulith"))
-					.forEach(packages::add);
+					.forEach(packagesToSet::add);
 
-			definition.getConstructorArgumentValues().addIndexedArgumentValue(0, packages.toArray(String[]::new));
+			definition.getConstructorArgumentValues().addIndexedArgumentValue(0, packagesToSet.toArray(String[]::new));
 		}
 	}
 }