feature(unlock-app): Add default `opengraph` metadata

[0xTxbi]

Description

This PR introduces default SEO metadata for the Unlock App to ensure OpenGraph and Twitter cards are consistently populated across all pages.

Key updates include:

• Setting default OpenGraph values to align with branding.
• Adding a custom image specifically for the Prime page.
• Ensuring all updates integrate seamlessly with existing tags currently managed by NextSeo without disrupting them.

Issues

Fixes #14905 Refs #14905

Checklist:

• [x] 1 PR, 1 purpose: my Pull Request applies to a single purpose
• [x] I have commented my code, particularly in hard-to-understand areas
• [ ] I have updated the docs to reflect my changes if applicable
• [ ] I have added tests (and stories for frontend components) that prove my fix is effective or that my feature works
• [x] I have performed a self-review of my own code
• [ ] If my code involves visual changes, I am adding applicable screenshots to this thread

[0xTxbi]

LGTM!

As a follow up PR should we get rid of nextSeo?

yes, we definitely should! on it!