Missing Comma in default horizon_keystone_multidomain_choices variable

[Sven Anders]

The horizon_keystone_multidomain_choices is wrong.

The login form is not shown when, but an error message, when you use it.

It should be:
```
horizon_keystone_multidomain_choices: "(('{{ horizon_keystone_default_domain }}', '{{ horizon_keystone_default_domain }}'),)"
```
missing comma at the end, in the original version

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/openstack-ansible-os_horizon/+/826310

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/openstack-ansible-os_horizon/+/826310
Committed: https://opendev.org/openstack/openstack-ansible-os_horizon/commit/db1bd3091d686040daeac01da34df629303061e0
Submitter: "Zuul (22348)"
Branch: master

commit db1bd3091d686040daeac01da34df629303061e0
Author: Dmitriy Rabotyagov <email address hidden>
Date: Tue Jan 25 17:22:04 2022 +0200

    Fix default multidomain choices

    We're missing comma at the end of set, which leads to error.

    We additionally define condition when choices will be added to config.

    Change-Id: I6b1c24fae22e9adb9e16fade4229d5761ac0b520
    Closes-Bug: #1958645

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/openstack-ansible-os_horizon yoga-eom release.