ansible-core>=2.19.0 only auto-parses YAML files, not JSON.

Previous ansible-core versions auto-parsed JSON as well, but ansible-core>=2.19.0
doesn't, so we added a `from_json` post-filter.
However, older versions auto-parsing JSON and turning it into a dict, on
which we later run `from_json` is no good.

In this patch, we try to equalize behavior and configure Ansible to never parse JSON,
hopefully making old-Ansible behave like new Ansible.

Related to https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/4458

Ref: https://docs.ansible.com/ansible/latest/collections/ansible/builtin/template_lookup.html#parameter-convert_data