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).

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• All CI checks are passing and the changes look good in the review environment.

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[sunbrye]

@ShyneChikwapulo Thanks for making the update! LGTM ✅

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[ShyneChikwapulo]

Thanks for reviewing and merging this one as well, @sunbrye! I appreciate your help.😇