Fix tuples to actually be tuples (#52591)

lib/ansible/modules/system/cron.py

@@ -583,10 +583,10 @@ def main():
             ['insertafter', 'insertbefore'],
         ],
         required_by=dict(
-            cron_file=('user'),
+            cron_file=('user',),
         ),
         required_if=(
-            ('state', 'present', ('job')),
+            ('state', 'present', ('job',)),
         ),
     )
 

lib/ansible/modules/system/firewalld.py

@@ -648,8 +648,8 @@ def main():
         ),
         supports_check_mode=True,
         required_by=dict(
-            interface=('zone'),
-            source=('permanent'),
+            interface=('zone',),
+            source=('permanent',),
         ),
     )
 

lib/ansible/modules/system/interfaces_file.py

@@ -361,7 +361,7 @@ def main():
         add_file_common_args=True,
         supports_check_mode=True,
         required_by=dict(
-            option=('iface'),
+            option=('iface',),
         ),
     )