ci: only install chromium for playwright

[sapphi-red]

Description

playwright install installs all default browsers (microsoft/playwright#14862).
But as we are using playwight-chromium, other browsers are not needed.
This PR changes the command to explicitly install chromium only.

Also this part is needed because of pnpm/pnpm#4888.

refs #8041

Additional context

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What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

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