feat(vitest/valid-expect-in-promise): add rule

[cardoso]

Adapted from jest/valid-expect-in-promise.

This is the only rule I'm missing after migrating from jest, so it'd be nice to have it in order to depend only on @vitest/eslint-plugin .

[veritem]

@cardoso this pr looks great. would you mind making necessary changes to support this?

- expect.poll(() => getElement()).toBeVisible()
+ await expect.poll(() => getElement()).toBeVisible()

[cardoso]

@veritem After trying a bit I'm starting to think the expect.poll or expect.element case should be covered by a separate rule. This one is very specific about finding expect inside promises and I couldn't find a simple way to also cover those cases. What do you think?

[veritem]

@cardoso i agree.

[veritem]

thanks you!