fix another script validation issue (#1774)

* fix another script validation issue

* add test for changing script to str None

* cleanup change_script tests

sabnzbd/nzbqueue.py

@@ -276,7 +276,7 @@ class NzbQueue:
 
     def change_script(self, nzo_ids: str, script: str) -> int:
         result = 0
-        if is_valid_script(script):
+        if (script is None) or is_valid_script(script):
             for nzo_id in [item.strip() for item in nzo_ids.split(",")]:
                 if nzo_id in self.__nzo_table:
                     self.__nzo_table[nzo_id].script = script

tests/test_functional_api.py

@@ -715,8 +715,8 @@ class TestQueueApi(ApiTestFunctions):
                 False,
                 marks=pytest.mark.skipif(sys.platform.startswith("win"), reason="Not for Windows"),
             ),
-            (None, True, False),
+            ("None", False, True),
-            ("", True, False),
+            ("", False, False),
         ],
     )
     def test_api_queue_change_job_script(self, script_filename, create_scriptfile, should_work):