Migrate OpenShift 4.18 release pipelines to use the common Konflux pipeline template from main branch, removing duplicate pipeline definitions and standardizing on shared configuration.

Why

The 4.18 pipelines are using older, duplicated pipeline definitions. Migrating to the common pipeline on main branch will:

• Reduce maintenance overhead (single pipeline to update)
• Ensure consistency across release branches
• Automatically inherit improvements made to the common pipeline

Acceptance Criteria

• .tekton/control-plane-operator-4-18-pull-request.yaml migrated to use common pipeline
• .tekton/control-plane-operator-4-18-push.yaml migrated to use common pipeline
• Both pipelines tested and passing
• Old pipeline definitions removed or deprecated

Technical Details

Files to Modify

• .tekton/control-plane-operator-4-18-pull-request.yaml
• .tekton/control-plane-operator-4-18-push.yaml

Migration Target

Common pipeline template on main branch