Fix: Properly format --build-arg values in Podman image build task

[GSSparks]

Summary: This PR fixes an issue in the Molecule playbook where Podman build arguments were not being separated by whitespace, causing command-line parsing errors when passing complex values (e.g. values containing --dns, environment substitutions, etc.).

Problem: The original extra_args Jinja2 block rendered build arguments like this:
--build-arg=FOO=BAR --dns=1.2.3.4--build-arg=BAR=baz
Because there were no spaces between build arguments generated in the loop, arguments would be concatenated incorrectly, breaking the podman build command.

Fix: The fix uses Ansible's zip_longest filter to format --build-arg=KEY=VALUE strings cleanly and space-separated. This ensures that each argument is properly delimited, even when values contain CLI-like content.