Revert "Dark Mode issue#157"

[seanmarcia]

Reverts #246

[Copilot]

Pull Request Overview

This PR reverts changes related to dark mode functionality by removing the custom ThemeContext, ThemeToggleButton, and ColorStyles, and by reverting _app.tsx to a previous state that uses the ThemeProvider from @primer/react-brand.

• Removed custom dark mode context and provider
• Removed dark mode toggle button and related styling
• Cleaned up imports from components using dark mode specifics

Reviewed Changes

Copilot reviewed 8 out of 11 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
pages/_app.tsx	Reverted to using ThemeProvider from @primer/react-brand and removed custom theme functionality
context/ThemeContext.tsx	Entirely removed custom dark mode context
components/SDGFilter.tsx	Removed use of ColorStyles
components/LanguageFilter.tsx	Removed use of ColorStyles and consolidated Select props
components/Header/ThemeToggleButton.tsx	Removed dark mode toggle button component
components/Header/Header.tsx	Removed dark mode toggle component; manually set dark mode attribute
components/ColorStyles.tsx	Removed custom ColorStyles file

Files not reviewed (3)

• components/Header/Header.module.scss: Language not supported
• package.json: Language not supported
• styles/globals.scss: Language not supported