Correct machinectl become plugin function arguments (#58734)

* Correct get_option function name and change flags to become_flags

* Remove the '--' from the returned command

* add changelog fragment

* change changelog fragment description

* move the -q argument to machinectl before the shell argument to resolve issues with machinectl v230 (see #56571)

changelogs/fragments/58734-correct-machinectl-become-plugin.yaml

@@ -0,0 +1,2 @@
+bugfixes:
+  - machinectl become plugin - correct bugs which induced errors on plugin usage

lib/ansible/plugins/become/machinectl.py

@@ -81,7 +81,7 @@ class BecomeModule(BecomeBase):
         if not cmd:
             return cmd
 
-        become = self._get_option('become_exe') or self.name
-        flags = self.get_option('flags') or ''
+        become = self.get_option('become_exe') or self.name
+        flags = self.get_option('become_flags') or ''
         user = self.get_option('become_user') or ''
-        return '%s shell -q %s %s@ -- %s' % (become, flags, user, cmd)
+        return '%s -q shell %s %s@ %s' % (become, flags, user, cmd)