Add priorityclasses to high priority restore list

Fixes #4201: Ensure PriorityClasses are restored before pods that
reference them, preventing restoration failures when pods depend on
custom PriorityClasses.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>
Signed-off-by: Tiger Kaovilai <tkaovila@redhat.com>

changelogs/unreleased/9175-kaovilai

@@ -0,0 +1 @@
+Add priorityclasses to high priority restore list

pkg/cmd/server/config/config.go

@@ -117,6 +117,7 @@ var (
 			"secrets",
 			"configmaps",
 			"limitranges",
+			"priorityclasses",
 			"pods",
 			// we fully qualify replicasets.apps because prior to Kubernetes 1.16, replicasets also
 			// existed in the extensions API group, but we back up replicasets from "apps" so we want