Make sure siteIds are numbers

Fixes PAN-145

server/routers/client/updateClient.ts

@@ -29,7 +29,7 @@ const updateClientSchema = z
     .object({
         name: z.string().min(1).max(255).optional(),
         siteIds: z
-            .array(z.string().transform(Number).pipe(z.number()))
+            .array(z.number().int().positive())
             .optional()
     })
     .strict();