feat(search): update landing page to encompass talking points & registration

Description

This PR updates the Search landing page and registration process for Brave Search Ads. It introduces new content, layout changes, and a video demonstration of setting up a campaign. The changes aim to improve user experience and provide more information about Brave Search Ads.

Changes

### Changes 1. `src/search/SearchLandingPage.tsx`: - Completely redesigned the layout and content of the Search landing page. - Added a new video component showcasing how to set up a Brave Search Ads campaign. - Updated text content and messaging to focus on the benefits of Brave Search Ads. - Removed the image carousel and replaced it with more structured content sections. 2. `src/search/SearchTalkingPoints.tsx`: - Updated the talking points with new titles and descriptions. - Adjusted the layout and styling of the talking points section. 3. `src/auth/registration/SearchRegister.tsx`: - Modified the registration form layout and styling. - Updated the form submission button text. 4. `src/auth/registration/Register.tsx`: - Removed the SearchRegister route and added a redirect from "/register/search" to "/search". 5. `src/auth/registration/SearchForm.tsx`: - Adjusted the width of the form container. 6. `src/basic-attention-token/PrivacyPolicy.tsx`: - Added a conditional variant for the typography based on whether it's used in the search context. 7. `src/locales/*.po`: - Updated various translation strings to reflect the new content and messaging. 8. Added a new video file: `src/assets/videos/setting_up_brave_search_ads.mp4`

Possible Issues

The removal of the SearchRegister route in Register.tsx might affect existing links or user flows that depended on that route.
The changes to the layout and content might require updates to existing documentation or user guides.

Security Hotspots

None identified. The changes are primarily focused on UI and content updates, with no apparent security implications.

brave / ads-ui