Description of problem:

The applyACMBackupLabelToInstallTemplates() function call was accidentally removed from the ClusterInstance reconciliation loop during a linting/refactoring commit. While the function itself and its unit tests were preserved, the function is no longer invoked during reconciliation, making it effectively dead code. This breaks the ACM disaster recovery backup feature for custom installation template ConfigMaps.

The function was originally added in PR #120 (commit 79cfb6246bd1d78dcd339b590955ea388471dbb1) and accidentally removed in PR #181 (commit 4f9688feefaedb49522d8c106ad8671f71e9dc5c).

Version-Release number of selected component (if applicable): ACM 2.13

How reproducible: 100% reproducible

Steps to Reproduce:

1. Create a ClusterInstance CR with custom (non-default) installation template ConfigMaps

1. Apply the ClusterInstance to trigger reconciliation

1. Check the labels on the custom template ConfigMaps

1. Observe that the cluster.open-cluster-management.io/backup label is NOT applied

Actual results:

Custom installation template ConfigMaps (those not provided by the SiteConfig operator) should have the cluster.open-cluster-management.io/backup: "" label applied automatically during ClusterInstance reconciliation to enable ACM disaster recovery backup.

Expected results:

Custom installation template ConfigMaps (those not provided by the SiteConfig operator) should have the cluster.open-cluster-management.io/backup: "" label applied automatically during ClusterInstance reconciliation to enable ACM disaster recovery backup.

Additional info: