feat(clerk-js): Use stricter organization slug validation

[jacekradko]

Description

Related: https://github.com/clerk/clerk_go/pull/10933

Checklist

• pnpm test runs as expected.
• pnpm build runs as expected.
• (If applicable) JSDoc comments have been added or updated for any package exports
• (If applicable) Documentation has been updated

Type of change

• 🐛 Bug fix
• 🌟 New feature
• 🔨 Breaking change
• 📖 Refactoring / dependency upgrade / documentation
• other:

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Latest commit: 23b2c79

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Name	Status	Preview	Comments	Updated (UTC)
clerk-js-sandbox	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Jun 5, 2025 2:33am

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