update role to optional for user update

src/app/api/users/[userId]/route.ts

@@ -26,7 +26,10 @@ export async function POST(request: Request, { params }: { params: Promise<{ use
   const schema = z.object({
     username: z.string().max(255),
     password: z.string().max(255).optional(),
-    role: z.string().regex(/admin|user|view-only/i),
+    role: z
+      .string()
+      .regex(/admin|user|view-only/i)
+      .optional(),
   });
 
   const { auth, body, error } = await parseRequest(request, schema);