CI: Add detection for unplanned rolling updates during cluster self-updates

Summary

Add detection for unplanned Machine rolling updates that occur when a cluster's own update (management or workload) triggers unwanted Machine recreation due to configuration changes. Current detection only covers cross-cluster scenarios but misses self-cluster rolling updates.

Related references

• Issue #2218 (closed) - Original issue identifying unplanned rolling update scenarios
• !4705 (merged) - MR implementing cross-cluster detection

Details

Purpose: Implement detection for cluster self-update rolling updates to complete the coverage of unplanned Machine rolling update scenarios.

Problem: When updating a cluster, changes to metallb, calico, or coredns can trigger unplanned Machine rolling updates within the same cluster. The existing cluster-machines-ready reconciliation timestamp approach doesn't work for self-updates because if unwanted Machines are created, the reconciliation waits for them and completes after they exist, making the timestamp useless as a reference.

cc- @tmmorin