Fix: GeometrisElement.Intersection method

[katehryhorenko]

BACKGROUND:
I changed the GeometricElement.Intersection method to support RepresentationInstances. I playing with Stocking Plan Exporter and noticed that sometimes pdf contains wrong geometry:

DESCRIPTION:

• The issue was that I have changed prev. this method to collect intersection points and only after that add them to the graph. And for the case below it doesn't work:
  

I changed method to add points like it was before

TESTING:

REQUIRED:

• All changes are up to date in CHANGELOG.md.

COMMENTS:

• Change log contains data that Intersection method was changed

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This change is 

[wynged]

Reviewed 2 of 2 files at r1, all commit messages.
Reviewable status: complete! 1 of 1 approvals obtained