[eng] have verify autorest warn instead of raise (Azure#20913)

Author: iscai-msft

eng/pipelines/templates/steps/verify-autorest.yml

@@ -34,6 +34,7 @@ steps:
 
     - task: PythonScript@0
       displayName: 'Verify autorest'
+      continueOnError: true
       inputs:
         scriptPath: 'scripts/devops_tasks/verify_autorest.py'
         arguments: >-

scripts/devops_tasks/verify_autorest.py

@@ -8,7 +8,6 @@
 import argparse
 import os
 import logging
-import sys
 
 from common_tasks import run_check_call