Add duplicate workflow prevention in MetadataExtractor

Integrate DuplicateEntityWorkflowFinder to prevent creating workflows for entities with existing opened or positive final workflows. Updated EntityWorkflowVoter to implement the same check before allowing creation. Removed unnecessary blank workflow parameter from Twig template.

src/Bundle/ChillMainBundle/Workflow/Templating/WorkflowTwigExtensionRuntime.php

@@ -59,7 +59,6 @@ class WorkflowTwigExtensionRuntime implements RuntimeExtensionInterface
 
         return $environment->render('@ChillMain/Workflow/_extension_list_workflow_for.html.twig', [
             'entity_workflows_json' => $this->normalizer->normalize($entityWorkflows, 'json', ['groups' => 'read']),
-            'blank_workflow' => $blankEntityWorkflow,
             'workflows_available' => $workflowsAvailable,
             'relatedEntityClass' => $relatedEntityClass,
             'relatedEntityId' => $relatedEntityId,