Horizon: Stop setting CA certificate for client authentication

... because we do not intend to implement it by tls-e. Currently
deployment is failing with the following error when tls-e is enabled,
because ca cert is given without ssl_verify_client, which was removed
by I7d3f833cf36d7169a0fbc25d133284e06d3f1468 .

```
The ssl_verify_client parameter is required when setting ssl_ca
```

Closes-Bug: #2031599
Depends-on: https://review.opendev.org/c/openstack/tripleo-ci/+/891650
Related: rhbz#2193388
Change-Id: I329f492570fbb559db73298285a8c624603bdc3d

deployment/horizon/horizon-container-puppet.yaml

@@ -241,9 +241,6 @@ outputs:
           # NOTE(tkajinam): The heat-dashboard parmaeters are now defined in an independent file,
           #                 so should be removed from the base local_settings.
           horizon::enable_user_pass: 'UNSET'
-        - if:
-          - {get_param: EnableInternalTLS}
-          - horizon::horizon_ca: {get_param: InternalTLSCAFile}
         - if:
           - {get_param: WebSSOEnable}
           - horizon::websso_enabled: