Bar and column true stroke and fill paths

[rosco54]

This is a request to consider restoring a visual feature that was removed from the repository main branch (the change has not yet been released).

The feature was removed as part of recent improvements to corner radius rendering but the change did not reference any issue number or provide a rationale in the commit for this specific change, which does not appear to affect corner radii AFAIKS.

The feature is best illustrated:

Without the feature

1. At least one existing sample chart doesn't render as expected. Example: a column chart that defines a stroke width of 2 and transparent color expecting to show a gap between columns. No gap appears because fills abutt.
   

2. Stacked column chart with stroke outlines that:
   . overlap
   . require the viewer to visually disambiguate
   . looks untidy
   

With the feature

1. The gap is now visible.
   

2. Stacked column chart that looks clean and visually unambiguous.
   

Improvements

Works as expected for stacked bars/columns with negative values

Works as expected for reversed axis charts

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• My branch is up to date with any changes from the main branch