Change the raw module's detection of environment settings. (#15535)

The task_vars datastructure always contains an environment key,
so use the _task.environment property to look for a non-empty
list instead.

lib/ansible/plugins/action/raw.py

@@ -26,10 +26,8 @@ class ActionModule(ActionBase):
     def run(self, tmp=None, task_vars=None):
         if task_vars is None:
             task_vars = dict()
-        else:
-            if 'vars' in task_vars:
-                if 'environment' in task_vars['vars']:
-                    # The environment key only exists if explicitly declared in the task or in the play
+
+        if self._task.environment:
             self._display.warning('raw module does not support the environment keyword')
 
         result = super(ActionModule, self).run(tmp, task_vars)