Fix Helm chart RBAC template to handle empty rule arrays

[naptalie]

Summary

• Fixes RBAC template rendering failure when rbac.rules or rbac.clusterRules are set to empty arrays
• Adds conditional checks to output valid YAML empty array syntax when rule arrays are empty
• Includes test case for empty RBAC rules configuration

Problem

The Grafana Alloy Helm chart fails to template when rbac.rules or rbac.clusterRules configuration fields are set to empty arrays. This produces a YAML parsing error because the toYaml filter outputs an empty string for empty arrays, leaving the rules: key without a valid value.

Solution

Modified rbac.yaml to:

1. Check if rule arrays have content before rendering
2. Output valid YAML empty array syntax [] when arrays are empty
3. Handle both Role and ClusterRole configurations

Test Plan

• Added test case configuration in rbac-empty-rules-values.yaml
• Verified template renders successfully with empty RBAC rules:

  helm template test charts/alloy -f charts/alloy/ci/rbac-empty-rules-values.yaml

• Generated test outputs verify valid YAML structure

Fixes #4778

🤖 Generated with Claude Code

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