Remove ara_default from callbacks_enabled (#12490)

The option ara_default was still present in ansible.cfg under callbacks_enabled.
This is a leftover from commit b9e9364 ("Remove ara support in CI") and should
have been removed together with the rest of the ara integration.

Signed-off-by: Ali Afsharzadeh <afsharzadeh8@gmail.com>

ansible.cfg

@@ -15,7 +15,7 @@ timeout = 300
 stdout_callback = default
 display_skipped_hosts = no
 library = ./library
-callbacks_enabled = profile_tasks,ara_default
+callbacks_enabled = profile_tasks
 roles_path = roles:$VIRTUAL_ENV/usr/local/share/kubespray/roles:$VIRTUAL_ENV/usr/local/share/ansible/roles:/usr/share/kubespray/roles
 deprecation_warnings=False
 inventory_ignore_extensions = ~, .orig, .bak, .ini, .cfg, .retry, .pyc, .pyo, .creds, .gpg