fix tagged implicit gathering (#48294)

* fix tagged implicit gathering

 - None is not tHe default anymore, its an empty list

* Update changelogs/fragments/fix_taggged_gather.yml

Co-Authored-By: bcoca <bcoca@users.noreply.github.com>

changelogs/fragments/fix_taggged_gather.yml

@@ -0,0 +1,2 @@
+bugfixes:
+    - now default is ``list`` so ``None`` is bad comparison for gathering

lib/ansible/executor/play_iterator.py

@@ -180,7 +180,7 @@ class PlayIterator:
         }
 
         # Unless play is specifically tagged, gathering should 'always' run
-        if self._play.tags is None:
+        if not self._play.tags:
             setup_task.tags = ['always']
 
         if gather_timeout: