Add a way to change what menu::Confirm does in the recent projects modal (#8688)

Follow-up of
https://github.com/zed-industries/zed/issues/8651#issuecomment-1973411072

Zed current default is still to reuse the current window, but now it's
possible to do
```json
"alt-cmd-o": [
  "projects::OpenRecent",
  {
    "create_new_window": true
  }
]
```
and change this.

menu::Secondary confirm does the action with opposite window creation
strategy.

Release Notes:

- Improved open recent projects flexibility: settings can change whether
`menu::Confirm` opens a new window or reuses the old one

crates/zed/src/app_menus.rs

@@ -37,7 +37,12 @@ pub fn app_menus() -> Vec<Menu<'static>> {
                 MenuItem::action("New Window", workspace::NewWindow),
                 MenuItem::separator(),
                 MenuItem::action("Open…", workspace::Open),
-                MenuItem::action("Open Recent...", recent_projects::OpenRecent),
+                MenuItem::action(
+                    "Open Recent...",
+                    recent_projects::OpenRecent {
+                        create_new_window: false,
+                    },
+                ),
                 MenuItem::separator(),
                 MenuItem::action("Add Folder to Project…", workspace::AddFolderToProject),
                 MenuItem::action("Save", workspace::Save { save_intent: None }),