Dashboard Migrations: V3 - no-op; remove v3 from DashboardMigrator.ts (#112239)

apps/dashboard/pkg/migration/schemaversion/v3.go

@@ -0,0 +1,9 @@
+package schemaversion
+
+import "context"
+
+// V3 is a no-op migration
+func V3(_ context.Context, dashboard map[string]interface{}) error {
+	dashboard["schemaVersion"] = 3
+	return nil
+}