Add golden test

[jpnurmi]

Ref: ubuntu/yaru.dart#848

[Feichtmeier]

@d-loose @robert-ancell we really need this PR to become better with detecting visual regressions
Could you help with finishing this?

[d-loose]

I'm definitely in favor of adding those tests - I don't know how much work is left to be done and when/if I have time to focus on that, though.

[github-actions]

No release type found in pull request title "Add golden test". Add a prefix to indicate what kind of release this pull request corresponds to. For reference, see https://www.conventionalcommits.org/

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