Trivial fix

Author: SteveSandersonMS

scripts/codegen/utils.ts

@@ -483,7 +483,7 @@ export function resolveObjectSchema(
 
     const singleBranch = (resolved.anyOf ?? resolved.oneOf)
         ?.filter((item): item is JSONSchema7 => {
-            if (typeof item !== "object") return false;
+            if (!item || typeof item !== "object") return false;
             const s = item as JSONSchema7;
             // Filter out null types and `{ not: {} }` (Zod's representation of "nothing" in optional anyOf)
             if (s.type === "null") return false;