Dark mode colors: Stacked column chart (cross-column colors)
## Problem
- From this issue: https://gitlab.com/gitlab-org/gitlab-services/design.gitlab.com/-/issues/619
- Transparency in charts + dark mode = disaster
## Solution
Update stacked column chart dark mode color scheme.
#### Color Sequence
Color sequence follows similar pattern to light mode
- Set 1
- $dv-blue-300
- $dv-orange-300
- $dv-aqua-300
- $dv-green-300
- $dv-magenta-300
- Set 2
- $dv-blue-500
- ...
- Set 3
- $dv-blue-100
- ...
#### Gap
- Create a 1px gap to differentiate column stacks further
#### Hovering
While hovering over columns:
- 2px white border (inner radius) across entire stacked column
- Saturate color by an extra 200 (for example $dv-blue-300 >>> $dv-blue-500)
- Fill opacity 80%
## Links
- [Figma Prototype](https://www.figma.com/proto/geVX9QT1KJiCCDAtBy8AQ0/Dark-mode?node-id=32%3A0&viewport=324%2C234%2C0.3224157989025116&scaling=min-zoom)
- [Figma file](https://www.figma.com/file/geVX9QT1KJiCCDAtBy8AQ0/Dark-mode?node-id=19%3A413)
- https://design.gitlab.com/data-visualization/color
issue