Dividers option to be removed

[stockiNail]

Discussed in #170

^{Originally posted by stockiNail December 12, 2022}
Having a look to the dividers option, it is not clear to me if the current bahvior is the wished one or not.

At the moment, setting the dividers option, the box is splitted by 2, ignoring the amount of subelements.

In the sample (https://chartjs-chart-treemap.pages.dev/samples/dividers.html), the passed data are the following:

const data = [
  {category: 'main', value: 1},
  {category: 'main', value: 2},
  {category: 'main', value: 3},
  {category: 'other', value: 4},
  {category: 'other', value: 5},
];

and my expectation, maybe wrong, grouping by category, is to have 2 boxes with 2 dividers for main and 1 for other. Instead, there is 1 divider for main and 1 for other.