feat(19255): Add safeguards for deleting nodes or edges on the Designer

[vanch3d]

See https://hivemq.kanbanize.com/ctrl_board/57/cards/19255/details/

The PR remove the uncontrolled deletion of nodes and edges on the Rect Flow canvas by adding user confirmation and safeguards.

The PR also fixes https://hivemq.kanbanize.com/ctrl_board/57/cards/20301/details/

Design

• Both DELETE and BACKSPACE keys are now supported
• Apply deletion on individually selected nodes or edges or on grouped selections. In both cases, all orphan edges will also be deleted
• If deletion is possible, a confirmation modal will require user intervention before being applied. There is no further feedback once the deletion is done (elements are immediately removed)
• If the deletion is not possible (see below), an error toast will provide reasons for the error
• The deletion operation cannot be reversed

The deletion verifies the validity of the process before being applied. The following rules are in place:

• If the Designer is in READ-ONLY mode (triggered by "View" CTA), no deletion is possible
• If the Designer is in DRAFT mode (triggered by "Create new" CTA), every element on the canvas can be deleted
• If the Designer is in LOADED (triggered by "Edit" CTA) or MODIFIED (triggered by a change in the policy), deletions are authorised except for the following reasons:
  • The Data Policy or Behaviour Policy nodes cannot be deleted once they have been published
  • The Topic Filter node cannot be deleted
  • The connection between a Topic Filter and a Data Policy cannot be deleted

Before

After