Description:
The InformedWatcher in knative/pkg/configmap/informer/informed_watcher.go crashes when handling cache.DeletedFinalStateUnknown objects during ConfigMap deletion events.

Error:
panic: interface conversion: interface {} is cache.DeletedFinalStateUnknown, not *v1.ConfigMap

Impact:

• Causes webhook pods to crash and restart repeatedly

Root Cause:
Unsafe type assertion in event handlers doesn't handle DeletedFinalStateUnknown objects

Proposed Fix:
Add safe type assertion with DeletedFinalStateUnknown handling