The debian 10 repository has been officially disabled: https://osmocom.org/news/308
However we just re-enabled a subset of the packages, osmo-gbproxy + dependencies, because currently they are relevant for a customer. Adjust the repo-install-test to deal with this subset of packages for debian 10 to fix that it is currently failing.
I have verified that repo-install-test works with this change for debian 10, 11 and 12. It currently doesn't run for debian 13 yet (OS#6934).