Problem:
Some of our dependencies seem to be abandoned (vue-jest, ...).
This causes us to not be able to update several other dependencies like jsdom anymore.

Solution strategy:
Switch from jest to vitest as a test framework.
This means:

• we need to probably touch every test in the frontend repository, update the syntax, figure out special cases (not supported test features, ...)

e.g.:
https://github.com/wmde/fundraising-app-frontend/pull/726