Fix CI tests

Currently the tests don't run through, see https://gitlab.tugraz.at/dbp/middleware/checkin/campus-qr/-/jobs/20990#L135.

> Task :serverTest
com.studo.campusqr.ContactTracingTest[server] > testContactTracing[server] FAILED
    java.lang.IllegalArgumentException at MainDatabase.kt:50
        Caused by: java.lang.IllegalArgumentException at MainDatabase.kt:50
com.studo.campusqr.ContactTracingTest[server] > testTransitThreshold[server] FAILED
    java.lang.IllegalArgumentException at MainDatabase.kt:50
        Caused by: java.lang.IllegalArgumentException at MainDatabase.kt:50

See https://gitlab.tugraz.at/dbp/middleware/checkin/campus-qr/-/blob/fork/.gitlab-ci.yml

Edited Oct 21, 2020 by Bekerle, Patrizio