[next] fix(test): correctly provide props in test

[raimund-schluessler]

☑️ Resolves

• Fixes the way we provide props to the mount function in modal.spec.js for vue 3.

@susnux Since the tests passed even though we didn't provide the props correctly, I assume the tests don't really test anything. I didn't change it here though, since it is the same in master and should probably be fixed there, I think.

[susnux]

Since the tests passed even though we didn't provide the props correctly

Yes but the test utils have a fallback so it still set the props correctly:
https://github.com/vuejs/test-utils/blob/b1c2388c3422115f0a7d2627fe308f44f4145462/src/createInstance.ts#L173

[raimund-schluessler]

Yes but the test utils have a fallback so it still set the props correctly: https://github.com/vuejs/test-utils/blob/b1c2388c3422115f0a7d2627fe308f44f4145462/src/createInstance.ts#L173

Ah, thanks for the hint. I wasn't aware of this. They apparently think ahead 😆