ci(documentation): Improve integrity of documentation build

[d3xter666]

Currently, if there's a package update of ceratin documentation dependencies, we cannot be sure whether this can break the vitepress build.

This integrity test checks exactly this.

An example is #1295

[coveralls]

coverage: 94.318% (-0.03%) from 94.35%
when pulling ffd409c on improve-ci
into 28788f7 on main.

[matz3]

The commit message was changed, but the PR was still merged with the previous PR title (invalid according to commitlint).
I think we should consider using a merge queue with the commitlint check to prevent this. It already happened several times in the past.