chore(platform): bump runners workload auth

[casey-brooks]

Summary

• Bump runners_chart_version to 0.5.11 for Release runners chart for workload authz model support (PR #65) runners#66.
• Bump authorization_chart_version to 0.5.4 so the deployed authorization service includes the workload OpenFGA model.
• Bump the openfga_authorization module source ref to v0.5.4 in lockstep with the authorization chart.

Release

• Runners release: https://github.com/agynio/runners/releases/tag/v0.5.11
• Release workflow: https://github.com/agynio/runners/actions/runs/26538397043

Test & Lint Summary

• for d in stacks/k8s stacks/system stacks/deps stacks/ziti stacks/platform stacks/data stacks/routing stacks/apps; do terraform -chdir="$d" fmt -check; done — passed with no formatting errors.
• for d in stacks/k8s stacks/system stacks/deps stacks/ziti stacks/platform stacks/data stacks/routing stacks/apps; do terraform -chdir="$d" init -backend=false -input=false && terraform -chdir="$d" validate; done — 8 passed, 0 failed, 0 skipped.
• bash -n apply.sh && bash -n install-ca-cert.sh && bash -n .github/scripts/verify_platform_health.sh — passed with no shell syntax errors.
• git diff --check — passed with no whitespace errors.

Closes agynio/runners#66

[casey-brooks]

Test & Lint Summary

• for d in stacks/k8s stacks/system stacks/deps stacks/ziti stacks/platform stacks/data stacks/routing stacks/apps; do terraform -chdir="$d" fmt -check; done — passed with no formatting errors.
• for d in stacks/k8s stacks/system stacks/deps stacks/ziti stacks/platform stacks/data stacks/routing stacks/apps; do terraform -chdir="$d" init -backend=false -input=false && terraform -chdir="$d" validate; done — 8 passed, 0 failed, 0 skipped.
• bash -n apply.sh && bash -n install-ca-cert.sh && bash -n .github/scripts/verify_platform_health.sh — passed with no shell syntax errors.
• git diff --check — passed with no whitespace errors.

[casey-brooks]

@noa-lucent please review when available. This PR bumps runners to the new v0.5.11 release from agynio/runners#66 and updates authorization chart/module refs to v0.5.4 for the workload OpenFGA model.