Display endpoint names in API Responses area

[matKlju]

AS A service designer
I WANT the Assign modal to display unique API endpoint names in the response selection area
SO THATI can easily identify which endpoint each response belongs to when multiple API calls exist in a service.

##Description

Currently, the endpoint response area in the Assign modal lists available responses without clearly identifying their originating API endpoint.

##Update the section to:

Display each response grouped or labeled by its unique API endpoint name.
Add a section title:
Estonian: API vastused
English: API Responses

This improves readability when services contain multiple API requests.

##Acceptance Criteria

• The endpoint response area has a visible section title:
  • Estonian: API vastused
  • English: API Responses
• Every listed response displays the unique name of its originating API endpoint.
• Endpoint names are unique within the list.
• Response selection behavior remains unchanged.
• Existing variable assignment functionality continues to work as before.

Notes

Only the presentation of available endpoint responses changes.
No changes are required to the underlying response data or assignment logic.