detach attacker on transformation

[drbergman]

• the attack already (in 1.14.0) ends when the attacker transforms
• do not let the spring attachment persist after the transform as well

[drbergman]

Here's an example demonstrating the need. The attacker (grey cell) attacks the defender (red cell). The attacker transforms into an exhausted cell (yellow cell). Meanwhile, the defender is chemotaxing to the left and the spring attachment between the two persists even after the attack has ceased. I have also included the config and cells.csv to recreate from the template project.

https://github.com/user-attachments/assets/1ca37563-35df-4959-8374-b652a27bf8b4
PhysiCell_settings.txt
cells.csv