Fix showroom helm install for non-root EE containers

[rhjcd]

Summary

• The showroom role's check-and-install-helm.yaml uses become: true to install helm to /usr/local/bin with root ownership. RHDP execution environments run as uid 1000 without sudo installed, causing a fatal error: /bin/sh: sudo: command not found.
• Added a rescue block that catches the become failure and falls back to installing helm in ~/.local/bin (user-writable, no privileges needed).
• Set a _showroom_helm_binary fact pointing to whichever helm path was found or installed, and pass it via binary_path to the kubernetes.core.helm_template calls in both deploy-showroom-helm.yaml and deploy-showroom-helm-zerotouch.yaml.
• Fully backwards compatible: on hosts where become succeeds, behavior is unchanged.

Test plan

• Provision a showroom catalog item on an EE (non-root) environment and verify helm installs to ~/.local/bin without error
• Provision a showroom catalog item on a traditional (root-capable) host and verify the existing /usr/local/bin path still works