fix: link direction flow

[danlobo]

Description

Fixing direction flow of links

Related Issue

#108

Motivation and Context

Direction flow of links are inverted, no matter which port originated the drag.

How Has This Been Tested?

• Open https://antonioru.github.io/beautiful-react-diagrams/#/Ports
• Hover the mouse over the link. Flow is correct.
• Double click on link to remove it
• Drag port 1 (top right of start node) to port 4 (bottom left on Middle node)
• Hover the mouse over the new link. Flow is inverted.

Screenshots (if appropriate):

[583747346]

Double click on link to remove it？ how to trigger Onclick event ， I need handle the links values。