fixed code to actually check the parameter not key

also made rest conditional on unit being provided, previouslly it changed from being always required

fixes #23810 alternate to #23907

lib/ansible/modules/system/systemd.py

@@ -294,7 +294,7 @@ def main():
     }
 
     for requires in ('state', 'enabled', 'masked'):
-        if requires is not None and unit is None:
+        if module.params[requires] is not None and unit is None:
             module.fail_json(msg="name is also required when specifying %s" % requires)
 
     # Run daemon-reload first, if requested
@@ -303,6 +303,7 @@ def main():
         if rc != 0:
             module.fail_json(msg='failure %d during daemon-reload: %s' % (rc, err))
 
+    if unit:
         found = False
         is_initd = sysv_exists(unit)
         is_systemd = False