Update night colors for setup wizard.

- Add night mode color for the main background of the SetupWizard
- Also, add a custom drawable for text color so that it remains light
for enabled buttons.

Test: build CarSetupWizard, switch to night mode and verify that
background color changes.
Bug: 70509574

Change-Id: I5009ad4e7d16963cd0a96c6b612fa9565ecf9792