Allow setting constant width for bars and variable width for categories

### Feature Proposal

I have a bar chart with multiple datasets which include empty values. I use skipNull to hide the empty values. Currently each category has the same width, and the width of the bars is inversely proportional to the number of bars in a category. I'd like all bars in the chart to have the same width, and the categories to have variable widths.

This code demonstrates the issue: https://codesandbox.io/p/sandbox/icy-tdd-sj2wz7

This is more or less how I'd like the chart to look:

### Possible Implementation

_No response_