[JENKINS-37778] Fix test after merge

Something unrelated in the shared libraries caused the tests to fail
bumping the dependency down one version to fix that.
An npe caused bu the credentials folder property to not be correctly initialized also fixed.

pipeline-model-definition/pom.xml

@@ -148,7 +148,7 @@
     <dependency>
       <groupId>org.jenkins-ci.plugins.workflow</groupId>
       <artifactId>workflow-cps-global-lib</artifactId>
-      <version>2.4</version>
+      <version>2.3</version>
       <scope>test</scope>
     </dependency>
 

pipeline-model-definition/src/test/java/org/jenkinsci/plugins/pipeline/modeldefinition/steps/CredentialWrapperStepTest.java

@@ -82,6 +82,7 @@ public static void setup() throws Exception {
         store.addCredentials(Domain.global(), mixedEnvCred2);
 
         folder = j.jenkins.createProject(Folder.class, "testFolder");
+        folder.addProperty(new FolderCredentialsProvider.FolderCredentialsProperty(new DomainCredentials[0]));
         j.configRoundtrip(folder);
         CredentialsStore folderStore = folder.getProperties().get(FolderCredentialsProvider.FolderCredentialsProperty.class).getStore();
         StringCredentialsImpl sc = new StringCredentialsImpl(CredentialsScope.GLOBAL, mixedEnvCred1Id, "test", Secret.fromString(mixedEnvInFolderCred1Secret));