chore: added TS to open-browser file

[HannahThor]

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Summary

Added TS to open-browser file. I couldn't find any @types/open-browser package in the DefinitelyTyped repo, so left the @ts-expect-error.

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[github-actions]

📊 Benchmark results

Comparing with a79430f

• Dependency count: 1,347 (no change)
• Package size: 312 MB ⬇️ 0.00% decrease vs. a79430f
• Number of ts-expect-error directives: 993 ⬇️ 0.30% decrease vs. a79430f

[khendrikse]

This is awesome! Thank you so much for doing this :)