feat(themes): enable all palettes

[thetaPC]

Issue number: internal

---

What is the current behavior?

The new theming structure does not allow high contrast and high contrast dark to render properly. This can be seen when running a test that uses set-content.

What is the new behavior?

• High contrast and high contrast dark have been enabled to the testing environments
• The theme files for high contrast and high contrast dark have been added under themes.

Does this introduce a breaking change?

• Yes
• No

Other information

Colors preview

How to test:

1. Verify that tests related to palettes are passing especially those that use setContent
2. Verify that the preview page renders the right colors for each possible variation of palettes and themes