Added example for parent size behavior with node labels.

[soerendomroes]

I want to showcase all the different options I am always forgetting about node labels and what works and what does not work here.

I hope that this may help users or me in the future.

[Copilot]

Pull Request Overview

This PR adds a comprehensive example demonstrating how node label placement and parent size behavior work together in ELK (Eclipse Layout Kernel). The example showcases different label placement configurations and how they affect parent node sizing.

• Demonstrates various node label placement options (center, top, bottom, top-left) and their sizing effects
• Shows the difference between child nodes and parent nodes in label space reservation
• Illustrates the use of nodeSize.constraints and nodeSize.options for controlling label space allocation

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