Add 'Undo' to Todos in the Done tab

What does this MR do?

Added the ability to 'Undo' the todos marked complete in the 'Done' tab of the Todo dashboard. This is possible through the 'Add todo' button in the done tab.

Are there points in the code the reviewer needs to double check?

Why was this MR needed?

For issue #27114 (closed)

Screenshots (if relevant)

Before	After

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated
• API support added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

Closes #27114 (closed)