[NcSelect] border & box-shadow combination seems off in 9.3.1

Hey,

in the current release, the border & box-shadow combination looks off.

This is what it looks like while developing an app using nextcloud-docker-dev.

The inspector shows the following CSS being applied:

To check that it's not an issue in the app I'm developing, I cloned the official calendar app into the apps-extra directory, updated the dependency to 9.3.1, which resulted in the same "weird" look.

However, on https://nextcloud-vue-components.netlify.app/#/Components/NcSelect the border/box-shadow looks like it's supposed to:

I guess, it has something to do with this change:

https://github.com/nextcloud-libraries/nextcloud-vue/commit/1c4d8e19795e46c6b9c3313678bf15d5adf84b5b#diff-e220135f30cfa99bbb7f8f8c79e4d517b44dfacf958bd2a80ecfeb4a8a471a63R1124-R1126

.vs__dropdown-toggle {
	@include border.inputLikeBorder('.select--dark', '.select--legacy', var(--vs-border-color));
}

Start with the NcSelect component and inspect the .vs__dropdown-toggle rule using border.inputLikeBorder, especially the cited commit change. Reproduce the appearance in the reported 9.3.1 setup and compare it with the component shown on the documentation site; done means the border and box-shadow render consistently.