bitbox02/ui/menu: avoid premature drop of title

Without the use of `as_ref()`, the contents of the Option is moved
into the callback and dropped on return, creating a dangling
pointer.

Author: benma

src/rust/bitbox02/src/ui/ui.rs

@@ -279,15 +279,17 @@ pub fn menu_create(params: MenuParams<'_>) -> Component<'_> {
     };
     let title = params
         .title
-        .map(|title| crate::str_to_cstr_force!(title, MAX_LABEL_SIZE));
+        .map(|title| crate::util::str_to_cstr_vec(title).unwrap());
     let component = unsafe {
         bitbox02_sys::menu_create(
             c_words.as_ptr(),
             select_word_cb,
             select_word_cb_param,
             words.len() as _,
             // copied in C
-            title.map_or_else(|| core::ptr::null(), |title| title.as_ptr()),
+            title
+                .as_ref()
+                .map_or_else(|| core::ptr::null(), |title| title.as_ptr()),
             continue_on_last_cb,
             continue_on_last_cb_param,
             cancel_cb,