A11y: Do not force colors in the color swatch and icon series

[evictorero]

What is this feature?
Show the colors in the Color Swatch and the Icon Series when the Windows High Contrast mode is active.
When forced-colors is active, all shadows are removed. That is why the color swatch appears to be empty.
Grafana relies on colors to display data, when the High Contrast mode is on it still makes sense to display custom colors in some cases.

This PR addresses the ColorSwatch and the SeriesIcon components so a user with High Contrast mode can still interact with the data visualization colors.

Before

before-high-contrast-color-picker.mov

After

after-high-contrast-color-picker.mov

Fixes #66311

Special notes for your reviewer:
If you don't have a Windows machine, you can emulate the same behavior with Chrome.
Open dev tools, cmd+shift+P, type rendering, change Emulate CSS media feature forced-colors to active

Please check that:

• It works as expected from a user's perspective.
• If this is a pre-GA feature, it is behind a feature toggle.
• The docs are updated, and if this is a notable improvement, it's added to our What's New doc.