Ability to test Buttons in Test Widget

[matKlju]

AS A service creator
I WANT to test services that use Multi-Choice Question (MCQ) elements directly in the canvas test widget
SO THAT I can verify the logic, button flows and responses of MCQ-based nodes without leaving the Service Module

Description

Currently, MCQ (multi-choice) nodes/elements are not handled properly in this test flow (buttons are note rendered).

This task adds full support for MCQ elements / nodes in the test widget, aligned with how they behave for real end-users.

Acceptance Criteria

• Test Widget supports services that contain MCQ (multi-choice) nodes without errors.
• When an MCQ node is reached, the widget displays:
  • The MCQ question text.
  • The correct 2–4 buttons exactly as configured in the node.
• Clicking an MCQ button:
  • Sends the correct payload to the DSL.
  • Triggers the correct outgoing path of that MCQ node.
  • Continues the test flow and displays subsequent node outputs.
• Test widget can complete full service paths containing one or multiple MCQ nodes.
• Other node types (Määra, API Call, Message, etc.) continue to work unchanged.
• If an error occurs test widget will reference the broken node and appropriate error message

Scope:

• Dynamic choice node
• MCQ elements