feat: vitest require assertions

[manuel3108]

This came up in the maintainers chat. It's regarding this config: https://vitest.dev/config/#expect-requireassertions

If there is a test without an assertion, it will currently pass unnoticed. But then it's not a real test.

Paolo contacted the vitest team, and they said this was set as default a long time ago, to ease the migration process from Jest and so on. Since sv is used to create new projects and not to migrate old Jest projects, we are safe to set such useful constraints to the user.

This was mainly expected to change the vitest add-on, but I also change our internal vitest configs to avoid this in this repo as well.

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Latest commit: 9adf655

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commit: 9adf655

[manuel3108]

Ok, let's not enforce this on migrate it causes to many errors and is not something we are currently actively working on.
Edit: and the same for create