context menu gets stuck when sub menu is shown

### Windows Terminal version

1.24.11321.0

### Windows build number

10.0.26200.8655

### Other Software

clink 1.9.25.dc17e7

### Steps to reproduce

start terminal
press the `menu` key (usually to the right of the spacebar)
with the mouse click `split pane`
attempt to click on close tab or anything in the main popup not the split pane popup to choose an option not from the "split pane" menu
attempt to click anywere on the terminal background to dismiss the popup

### Expected Behavior

the sub menu is dismissed and the action (if one is clicked on) is performed

### Actual Behavior

the popup sub menu locks all mouse input - impossible to dismiss with the mouse.
pressing `esc` works but this is not how menus are supposed to work in applications.

Reproduce the issue in Windows Terminal using the Menu key, then choose Split pane and test mouse dismissal and selection from the main popup. Trace the context-menu handling involved in the split-pane submenu; done means mouse input is no longer blocked, the submenu dismisses, and main-menu actions or background clicks work without requiring Esc.

Written by the indexing model from the issue text.