Collision Counter should be off by default

[arouinfar]

Discovered during review for #30

@Nancy-Salpepi noticed that the Collision Counter is on by default, which differs from the published version the simulation.

Given that the Collision Counter isn't central to the primary learning goal (PV=NkT), let's keep it off by default.

[pixelzoom]

This bug was introduced by @zepumph in 1b7cbcb, way back on 1/9/23, apparently for work that he was doing in chipper. Fixed in the above commits.

@Nancy-Salpepi please verify in main, close if OK.

[Nancy-Salpepi]

Looks good in main. Closing.