update tabindex

apps/admin.saladeaula.digital/app/routes/_.$orgid.enrollments.buy/review.tsx

@@ -407,7 +407,7 @@ function PostcodeForm({ onChange }: PostcodeFormProps) {
 
   type Schema = z.infer<typeof formSchema>
 
-  const { control, handleSubmit, setError } = useForm({
+  const { control, handleSubmit, setError, formState } = useForm({
     resolver: zodResolver(formSchema)
   })
 
@@ -458,6 +458,7 @@ function PostcodeForm({ onChange }: PostcodeFormProps) {
                   <InputGroupButton
                     type="submit"
                     variant="secondary"
+                    tabIndex={formState.isSubmitted ? -1 : 0}
                     className="cursor-pointer"
                   >
                     {loading ? <Spinner /> : <SearchIcon />}