Retain Atom/Bond highlights when exporting as PNG and SVG

[AnnaKosol]

Background:
Highlight functionality has been added as part of #4984. However, there's an issue where highlights do not persist when saving the structure as an image.

Solution:
Implement support for retaining atom/bond highlights when exporting the structure as PNG or SVG. Currently, highlights are lost during the image export process. The solution should ensure that the selected highlights are accurately reflected and preserved in the saved image files (both PNG and SVG formats).