fix(helm): resolve ALB healthcheck template parsing with dig function (#61)

[spbolton]

Description

Fix ALB healthcheck template parsing errors by replacing direct nested value access with dig function for safe value retrieval. This provides backwards compatibility with partial ALB override configurations and resolves nil pointer evaluation errors in ingress-dotcms-cluster.yaml template.

Key Changes:

• Replace .Values.ingress.alb.healthcheck.* with dig function calls
• Replace .Values.ingress.alb.targetGroup.* with dig function calls
• Add sensible defaults for all healthcheck and targetGroup parameters
• Remove duplicate configuration from environments.prod section
• Maintain full backwards compatibility with existing override files

Testing:

• Validated template parsing with actual override files from staff-sandbox deployment
• Confirmed ALB annotations generate correctly with proper defaults
• Verified StatefulSet, Service, and Ingress resources render without errors

Changes

• [List the main changes made]

Testing

• [Describe testing approach]

Closes #61

Issue: Update health checks for consistent ALB and Statef