✨ Create new window tab as duplicate workspace

> [!IMPORTANT]
> The completion of #1648 might be required before progress on this issue can begin.

### Description

Currently when showing window tabs and clicking the + icon to the right of the window tab bar, it tries to create a new file. We should instead duplicate the workspace similar to #1648 but instead of it being in a new window, it will be a new window tab.

The following should be added in support of this feature:
- **Menu item:** File → New → Window Tab
- **Keyboard shortcut:** ⌘ T

### Screenshots

https://github.com/CodeEditApp/CodeEdit/assets/806104/666d1235-8143-4516-8a1a-ebbba865d2fb