Fix for Variable defined multiple times (#397)

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Author: v1v

github/backport-active/backport_script.py

@@ -8,7 +8,6 @@ def main():
     github_token = os.environ['GITHUB_TOKEN']
     pr_number = int(os.environ['PR_NUMBER'])
     repository = os.environ['REPOSITORY']
-    labels_json = os.environ['PR_LABELS']
     backports_url = os.environ['BACKPORTS_URL']
     print(f"Using backports URL: {backports_url}")