Link Claude Sonnet 5.5 system card

[ShyneChikwapulo]

Why:

Closes #46252

What's being changed (if available, include any code snippets, screenshots, or gifs):

Updated the Claude Sonnet 5.5 entry in data/tables/copilot/model-comparison.yml to replace the "Coming soon" placeholder with a link to Anthropic's published [Claude Sonnet 5.5 System Card](https://www-cdn.anthropic.com/870c8f525702625d2c62fc6dd04c857e3250bec1/Claude%20Sonnet%205.5%20System%20Card.pdf).

Check off the following:

• A subject matter expert (SME) has reviewed the technical accuracy of the content in this PR.
• The changes in this PR meet the [GitHub Docs fundamentals](https://docs.github.com/en/contributing/writing-for-github-docs/about-githubs-documentation-fundamentals).
• All CI checks are passing and the changes look good in the review environment.

[welcome]

Thanks for opening this pull request! A GitHub docs team member should be by to give feedback soon. In the meantime, please check out the contributing guidelines.

[github-actions]

How to review these changes 👓

Thank you for your contribution. To review these changes, choose one of the following options:

• Spin up a codespace
• Set up a local development environment

A Hubber will need to deploy your changes internally to review.

Table of review links

Note: Please update the URL for your staging server or codespace.

This pull request contains code changes, so we will not generate a table of review links.

🤖 This comment is automatically generated.

[nexoracontrol-ops]

Why:

Closes #46252

What's being changed (if available, include any code snippets, screenshots, or gifs):

Updated the Claude Sonnet 5.5 entry in data/tables/copilot/model-comparison.yml to replace the "Coming soon" placeholder with a link to Anthropic's published [Claude Sonnet 5.5 System Card](https://www-cdn.anthropic.com/870c8f525702625d2c62fc6dd04c857e3250bec1/Claude%20Sonnet%205.5%20System%20Card.pdf).

Check off the following:

• A subject matter expert (SME) has reviewed the technical accuracy of the content in this PR.
• The changes in this PR meet the [GitHub Docs fundamentals](https://docs.github.com/en/contributing/writing-for-github-docs/about-githubs-documentation-fundamentals).
• All CI checks are passing and the changes look good in the review environment.