chore: [app-router-migration 35] migrate the "sso" pages

[r4zendev]

What does this PR do?

• This PR migrates the /auth/sso/* page group to the app directory (which runs under the App Router).
• The migrated page exists under /future/auth/sso/* and is accessible at all times.

Requirement/Documentation

• If there is a requirement document, please, share it here.
• If there is ab UI/UX design document, please, share it here.

Type of change

• [x] Chore (refactoring code, technical debt, workflow improvements)
• [x] New feature (non-breaking change which adds functionality)

How should this be tested?

There should be no changes between the old sso and new sso routes in terms of content and no downgrading in terms of performance. The pages were not tested due to being unable to reproduce the flow locally.

Mandatory Tasks

• [x] Make sure you have self-reviewed the code. A decent size PR without self-review might be rejected.

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📦 Next.js Bundle Analysis for @calcom/web

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This PR introduced no changes to the JavaScript bundle! 🙌