Enonic UI: X-Data toggler menu

[ashklianko]

Add a menu to the right of new Content Wizard tabs that will toggle available x-data forms. Enabling it will bring the new x data entry to the wizard tabs. See the design https://www.figma.com/design/qkrCEWujVxkjZBd2aI8YXI/content-studio-reskin?node-id=46788-185303&m=dev.

Things to note:

• A confirm button in the menu.
• Page to be displayed in the menu as disabled item
• Non-optional x-data to be disabled in the list
• Only optional x-data can be added/removed