Submenu alignment changed since 0.31.1

**Describe the bug**

If a submenu doesn't fit in the viewport, now the middle of it is visible, not the top.

Is there a way to affect this somehow?

See the code that does this here: https://github.com/ruffle-rs/ruffle/blob/3ada4296b2bd839f04d0c1dbee79caccb902bc7b/desktop/src/gui/menu_bar.rs#L242-L282

**To Reproduce**
Steps to reproduce the behavior:
1. Make a menu bar
2. Add a menu button to it
3. Add a submenu to one of the items
4. Add an item with reeeeeeeeeeaaaaaalllyy long text to this submenu

**Expected behavior**

The submenu is still usable even if it's too tall (should be scrollable maybe?).

**Screenshots**

See: https://github.com/ruffle-rs/ruffle/pull/20494#issuecomment-2968330821

**Additional context**

As also said in the linked issue comment, it might be up to us to trim/elide these long texts.
The cause might have been https://github.com/emilk/egui/pull/5716, dunno...